View source for Polish–Lithuanian War

{{Short description|Conflict between Poland and Lithuania, 1919-1920}}
{{infobox military conflict
| conflict          = Polish–Lithuanian War
| partof            = the [[Lithuanian Wars of Independence]] and the [[Polish–Soviet War]]<ref name=Seibt/><ref name=wrzosek/>
| image             = {{multiple image|border=infobox|perrow=2/2/2|total_width=300
|image1=Józef Piłsudski w Sejnach (22-320-1).jpg
|alt1=
|image2=Sejny Parada.jpg
|alt2=
|image3=Lithuanian soldiers of the Fifth Infantry Regiment in the forests of Vievis during the fighting with the Żeligowski's unit of the Polish Army.jpg
|alt3=
|image4=Commemoration of the Day of Independence of Lithuania on 16 February 1920 in Kaunas.jpg
|alt4=
|image5=Suvalkųsutartis1920-10-09.jpg 
|alt5=
|image6=Soldiers of the Lithuanian Army in Vilnius, Lithuania, 1920.jpg
|alt6=}}Clockwise from top left: {{flatlist|
* [[Józef Piłsudski]] in Sejny on 13 August 1919
* Polish cavalry parade in [[Sejny]]
* [[Antanas Smetona]] inspecting Lithuanian soldiers on 16 February 1920 in [[Kaunas]] during the commemoration of the [[Act of Independence of Lithuania]]
* The Lithuanian Army in [[Cathedral Square, Vilnius]] in 1920
* Lithuanian and Polish delegations negotiating the [[Suwałki Agreement]], October 1920
* The Lithuanian [[5th Infantry Regiment (Lithuania)|5th Infantry Regiment]] in [[Vievis]]' forests fighting against Żeligowski's soldiers in autumn 1920
}}
| date              = May 1919{{Sfn|Balkelis|2018|p=136}} – November 29, 1920<ref name=racis/>
| place             = [[Suwałki region|Suwałki]] and [[Vilnius region|Vilnius]] regions
| territory         = [[Suwałki region|Suwałki]] and [[Vilnius region|Vilnius]] regions ruled by Poland (with some adjacent areas) until 1939
| result            = Polish victory (''see {{slink||Aftermath}}'')
| combatant1        = {{plainlist|
*{{flagcountry|Second Polish Republic}}
*{{flagcountry|Republic of Central Lithuania}} (1920)
}}
| combatant2        = {{plainlist|
*{{flagicon|Lithuania}} [[Republic of Lithuania (1918–1940)|Lithuania]]
}}
| commander1        = {{plainlist|
*{{flagicon|Second Polish Republic|1919}} [[Józef Piłsudski]]
*{{flagicon|Second Polish Republic|1919}} [[Adam Nieniewski]]
*{{flagicon|Second Polish Republic|1919}} [[Lucjan Żeligowski]]
}}
| commander2        = {{plainlist|
*{{flagicon|Lithuania}} [[Silvestras Žukauskas]]
*{{flagicon|Lithuania}} [[Stasys Nastopka]]{{Surrender}}
*{{flagicon|Lithuania}} [[Antanas Smetona]]
*{{flagicon|Lithuania}} [[Mykolas Sleževičius]]
*{{flagicon|Lithuania}} [[Konstantinas Žukas]]
}}
| casualties1       = 264 dead (incomplete data)<ref name=vitkus/>
| casualties2       = 232 dead against the Polish army; 222 dead against Żeligowski's troops<ref name=vitkus>{{cite book |first=Gediminas |last=Vitkus |title=Lietuvos karai: Lietuvos XIX-XX a. nacionalinių karų sisteminė kiekybinė analizė |publisher= Generolo Jono Žemaičio Lietuvos karo akademija |year=2014 |isbn=978-609-437-250-6 | pages=197, 199 |language=lt}}</ref>
| campaignbox       = {{Campaignbox Establishment of Second Polish Republic}}
{{Campaignbox Polish–Lithuanian War}}
}}

The '''Polish–Lithuanian War''' was an [[undeclared war]] fought in the [[aftermath of World War I]] between newly independent [[Lithuania]] and [[Second Polish Republic|Poland]], with fighting mainly in the [[Vilnius Region|Vilnius]] and [[Suwałki Region|Suwałki]] regions, which was part of the [[Lithuanian Wars of Independence]] and lasted from May 1919 to 29 November 1920.{{Sfn|Balkelis|2018|p=136}} Since the spring of 1920, the conflict happened alongside the wider [[Polish–Soviet War]]{{Sfn|Balkelis|2018|p=137}} and was affected by its progress. It was subject to unsuccesful international mediation at the [[Conference of Ambassadors]] and the [[League of Nations]].

After World War I, the military and political situation in the region was chaotic, as multiple countries, notably Lithuania, Poland, and Soviet Russia, vied with each other over control of overlaping areas.{{efn|Polish and Lithuanian claims overlapped in parts of the former [[Vilna Governorate|Vilna]], [[Grodno Governorate|Grodno]], and [[Suwałki Governorate|Suwałki]] governorates.{{Sfn|Balkelis|2018|p=136}}}} The Polish–Lithuanian conflict was centered on [[Vilnius]],{{Sfn|Balkelis|2018|p=136}} which the [[Council of Lithuania]] declared the capital of the [[Act of Independence of Lithuania|restored Lithuanian state]].{{Sfn|Weeks|2015|pp=110-111}} Control of Vilnius was transferred from Germans to Poles on January 2, 1919, but the Polish paramilitary lost the city to the Bolsheviks on {{awrap|January 5.{{Sfn|Łossowski|1996|pp=32–33}}}} The Polish Army [[Vilna offensive|seized Vilnius again]] on April 19, 1919{{Sfn|Łossowski|1996|pp=41–46}} and came in contact with the [[Lithuanian Army]] fighting in the [[Lithuanian–Soviet War]]. Despite the antagonism over Vilnius, the Lithuanian and Polish armies sometimes cooperated when fighting against a common enemy, the Bolsheviks.{{Sfn|Balkelis|2018|p=137}} As [[Lithuania–Poland relations|Lithuanian–Polish relations]] worsened, the [[Allies of World War I|Entente]] drew two demarcation lines in hopes to stall further hostilities. The lines did not please either side and were ignored. The first clashes between Polish and Lithuanian soldiers occurred on April 26 and May 8, 1919, near [[Vievis]].{{sfn|Lesčius|2004|p=252}} With the [[1919 Polish coup attempt in Lithuania|Polish coup against the Lithuanian government]] failing in August 1919, the front stabilized until the summer of 1920.

In July 1920, Polish forces retreated due to reverses in the Polish–Soviet War and the Lithuanians followed the retreating troops to secure their lands as delineated in the [[Soviet–Lithuanian Peace Treaty]]. However, the Red Army was the first to enter Vilnius. In August 1920, Poland won the [[Battle of Warsaw (1920)|Battle of Warsaw]] and forced the Soviets to retreat. The Polish Army encountered Lithuanian opposition, defending their new borders, which the Polish government considered illegitimate. Thus, the Polish invaded Lithuanian-controlled territory during the [[Battle of Sejny]]. Pressured by the League of Nations, Poland signed the [[Suwałki Agreement]] on October 7, 1920. The agreement left the [[Suwałki region]] on the Polish side and drew a new incomplete demarcation line, which left Vilnius vulnerable to a [[flanking maneuver]].{{Sfn|Balkelis|2018|p=150|loc="In essence, the Lithuanians had to give up the Suwałki region, including Sejny, Giby, and Punsk."}}

On October 8, 1920, Polish general [[Lucjan Żeligowski]] staged a [[Żeligowski's Mutiny|mutiny]], secretly planned and authorized by the Polish chief of state [[Józef Piłsudski]]. Żeligowski's forces marched on Vilnius and captured it one day before the [[Suwałki Agreement]] was to formally come into effect.{{Sfn|Senn|1966|p=49}} Żeligowski proclaimed the creation of the [[Republic of Central Lithuania]] with its capital in Vilnius. Their [[Central Lithuanian Offensive on Kaunas|further offensive]] towards [[Kaunas]], the [[temporary capital of Lithuania]], was halted by the Lithuanians, who thus defended their independence. On November 29, 1920, a ceasefire was signed. Overall, from early 1919 to late 1920, Vilnius would switch rule{{efn|The Lithuanian government was established in [[Vilnius]] in November 1918{{Sfn|Sužiedėlis|2011|p=xxvii}} and attempts were made to organize a Lithuanian Army.{{Sfn|Balkelis|2018|pp=59, 63}}{{Sfn|Budreckis|1963|p=263-264}} On 2 January 1919, the Lithuanian government and Taryba evacuated the city,{{Sfn|Łossowski|1996|p=31}} while the [[Ober Ost|Germans]] gave control over Vilnius to the local Poles that same day.{{Sfn|Lesčius|2004|p=247}}{{Sfn|Łossowski|1996|p=31}} The Polish forces lost Vilnius to the [[Red Army]] several days later, on January 5.{{Sfn|Łossowski|1996|pp=32–33}} The Polish Army [[Vilna offensive|recaptured the city]] from the Bolsheviks in April 1919 and it remained under Polish control until July 1920.<ref>{{cite book |last1=Lerski |first1=George J. |title=Historical Dictionary of Poland |date=1996 |publisher=[[Greenwood Press]] |isbn=0313260079 |page=630}}</ref>{{Sfn|Łossowski|1996|pp=41-46, 121}}}} as many as seven times between Lithuanians, Poles and the Bolsheviks.{{Sfn|Balkelis|2018|p=136}} The Republic of Central Lithuania was incorporated into Poland as the [[Wilno Voivodeship (1926–1939)|Wilno Voivodeship]] in 1922. The prolonged mediation by the League of Nations did not change the situation and the ''[[status quo]]'' was accepted in 1923. In March 1923, the [[Conference of Ambassadors]] recognized the armistice line as a [[de jure]] Polish–Lithuanian border, awarding Vilnius to Poland.{{Sfn|Sužiedėlis|2011|p=319}}{{Sfn|Lojkó|2005|pp=271-273}} However, the [[International Court of Justice]] in [[The Hague]] arbitrated in 1931 that Poland broke international law by occupying Vilnius.<ref>{{Cite book |last=Miniotaitė |first=Gražina |title=Bordering Russia: Theory and Prospects for Europe's Baltic Rim |date=1998 |publisher=[[Ashgate Publishing]] |isbn=9780429862885 |editor-last=Mouritzen |editor-first=Hans |chapter=7: Lithuania}}</ref> Lithuania remained adamant regarding its claim to Vilnius as its constitutional capital throughout the whole interwar,{{Sfn|Lojkó|2005|pp=271-273}} and breaking all [[Lithuania–Poland relations|diplomatic relations with Poland]] due to the latter's control of the city. Diplomatic relations were only restored as a result of the March [[1938 Polish ultimatum to Lithuania]]. Vilnius was regained by Lithuania on {{awrap|28 October}} 1939, following the [[Soviet–Lithuanian Mutual Assistance Treaty]], twenty years after losing its capital. However, Lithuania as a whole lost its independence less than a year later following the [[Soviet ultimatum to Lithuania|Soviet ultimatum]] and [[occupation of the Baltic states]].

== Background ==

=== Demographic situation ===
{{Further|Demographic history of the Vilnius region}}
According to the [[Russian Empire Census|1897 Russian census]], the disputed city of Vilnius had a linguistic breakdown of {{awrap|30% Polish speaking,}} 40% Jews, and 2% Lithuanian speaking;<ref name="demoskop" /><ref name="loss1995" /> however the percentage of Lithuanian speakers in the surrounding countryside was a few times higher than that of Polish speakers – the population was 35% Lithuanian and 12% Polish speaking in [[Vilensky Uezd|Vilnius county]] (if excluding its centre - [[Vilnius]] city),<ref>{{Cite web|title=Vilnius district without urban population|url=http://www.demoscope.ru/weekly/ssp/rus_lan_97_uezd_eng.php?reg=92}}</ref> while [[Troki uezd|Trakai county]] had 59% Lithuanian and 11% Polish speaking population.<ref>{{Cite web|title=Trakai district – total population|url=http://www.demoscope.ru/weekly/ssp/rus_lan_97_uezd_eng.php?reg=110}}</ref> According to the 1916 German census, Poles were the most numerous among all local nationalities and constituted 53%{{sfn|Borzęcki|2008|p=10}} or 53.67% of the city's population,<ref name="Brensztejn" /> 50% in the entire Vilnius census region and the vast majority in the Vilnius census district.{{sfn|Borzęcki|2008|p=10}}

=== Military developments ===
[[File:PL-RU war 1919 phase II.svg|thumb|300px|The advance of Polish (blue arrows), Lithuanian/German (dark purple arrows) against the Soviet forces in early 1919. The blue line shows the Polish front in May 1920.]]
World War I ended when Germany signed the [[Armistice of 11 November 1918]]. On November 13, [[Russian Soviet Federative Socialist Republic|Soviet Russia]] renounced the [[Treaty of Brest-Litovsk]]<ref name=tarja/> and began the [[Soviet westward offensive of 1918–1919]]. The [[Bolsheviks]] followed retreating [[Imperial German Army]] troops and attacked Lithuania and Poland from the east trying to prevent their independence. They attempted to spread the [[World revolution|global proletarian revolution]], establish [[Soviet republics]] in the region, and join the [[German Revolution of 1918–1919|German]] and the [[Hungarian Soviet Republic|Hungarian Revolutions]].{{sfn|Rauch|1970|p=51}} The Soviet offensive sparked a series of local wars, including the [[Polish–Soviet War]] and the [[Lithuanian–Soviet War]].

At the end of 1918, four groups claiming authority existed in Vilnius: the occupational [[Ober Ost]]German government, which was preparing to leave the city; the Lithuanian government under [[Augustinas Voldemaras]] that had just begun creating the [[Lithuanian Army]]; the Polish Committee and the Polish Temporary National Council for Lithuania supported by armed units of the [[Self-Defence of Lithuania and Belarus]]; and [[Vilnius Soviet of Workers Deputies]] waiting for the [[Red Army]].{{Sfn|Lesčius|2004|p=245}} The Germans refused to provide weapons to Polish paramilitary units which intended to fight the approaching Red Army. The Ober Ost command also denied the Polish request to grant the [[Polish Land Forces]] free passage to Vilnius.<ref>{{cite book |last1=Böhler |first1=Jochen |date=2018 |title=Civil War in Central Europe, 1918-1921: The Reconstruction of Poland |publisher=[[Oxford University Press]] |isbn=978-0198794486|pages=85–86}}</ref>{{Sfn|Balkelis|2018|p=66}} The Polish Self-Defence was formally absorbed into the Polish Army at the end of December.{{sfn|Borzęcki|2008|p=11}} On 2 January 1919, Poles took over Vilnius from the retreating German troops and the fighting with the city's Bolshevik Worker's [[Soviet (council)|Soviet]] (capturing around 1,000 weapons{{Sfn|Balkelis|2018|pp=68-69}}).{{Sfn|Lesčius|2004|p=247}} Nonetheless, the last German soldiers left the city only on January 4.{{Sfn|Balkelis|2018|p=69}} The Lithuanian government failed to organize a defense of Vilnius.{{Sfn|Snyder|2003|pp=61-62|loc="The Lithuanian government, having failed to raise an army, evacuated exposed Vilnius for more westerly Kaunas"}}{{Sfn|Balkelis|2018|p=63|loc="We don't have any troops to defend Vilnius...only about 100 people" – [[Mykolas Sleževičius|Šleževičius]]' defense minister reported.}} Both the Polish and Lithuanian political leadership realized their inability to resist the invading Bolshevik forces.<ref>{{Cite book |last=Weeks |first=Theodore R. |url=http://worldcat.org/oclc/1241099006 |title=Vilnius between Nations, 1795-2000 |publisher=[[Northern Illinois University Press]] |year=2015 |isbn=978-1-5017-5808-9 |pages=112 |chapter=4 - World War I, 1914–1922 |oclc=1241099006}}</ref> So, on {{awrap|January 2}}, the [[Council of Lithuania]] evacuated from Vilnius to [[Kaunas]].<ref>{{Cite book |last=Rudling |first=Per Anders |url=http://worldcat.org/oclc/909236805 |title=The rise and fall of Belarusian nationalism, 1906-1931 |isbn=978-0-8229-6308-0 |editor-last=Harris |editor-first=Jonathan |series=Pitt Series in Russian and East European Studies |date=22 December 2014 |page=97 |oclc=909236805}}</ref> After some fighting, the local Polish forces lost Vilnius to the Bolsheviks on January 5.{{Sfn|Lesčius|2004|p=69}}{{Sfn|Łossowski|1996|pp=32–33}} Lithuanians relied on the aid of German troops to stop the Red Army offensive before it reached Kaunas.{{Sfn|Senn|1966|p=15}}

At first, the Soviets were successful but this came to a halt in February 1919 due to failures at the battles of [[Battle of Jieznas|Jieznas]], [[Battle of Kėdainiai|Kėdainiai]], and [[Battle of Alytus|Alytus]]. On February 5, Poland signed an agreement with Germany regulating the withdrawal of the German army from [[western Belarus]] and giving the Polish army the opportunity to march eastward. On February 14, 1919, Polish troops came into contact with the Bolshevik army near [[Vawkavysk]].{{Sfn|Wyszczelski|2008|p=54}} On April 16, 1919, the Polish Army launched a wide-ranging [[Vilna offensive|offensive against the Bolsheviks]] from [[Lida]] to Vilnius.{{Sfn|Łossowski|1996|p=45}} On April 19, 1919, the Polish cavalry under [[Władysław Belina-Prażmowski]] captured Vilnius.<ref name="davies" /> On April 22, 1919, Józef Piłsudski issued the ''[[Proclamation to the inhabitants of the former Grand Duchy of Lithuania]]'', in which he announced that the region's fate would be decided democratically. He also established the [[Civil Administration of the Eastern Lands]], headed by {{Ill|Jerzy Osmołowski|pl}}.{{Sfn|Łossowski|1996|pp=44–45}} An important strategic success for the Polish side was the capture of [[Grodno]] on April 28, 1919, from which the Germans withdrew.{{Sfn|Wyszczelski|2008|p=160}}

After that Polish troops advanced further west and northwest. The situation was utilized by the Lithuanian army, which entered Ukmergė on May 3, and started an offensive further south and southwest.{{Sfn|Balkelis|2018|p=137}} [[Polish–Lithuanian relations]] at the time were not immediately hostile, both armies met in several points ([[Merkinė]], [[Vievis]] and [[Širvintos]]), and even cooperated against the Bolsheviks in Giedraičiai area on May 11, 1919.{{Sfn|Balkelis|2018|pp=137-138}}

At first, both Poles and Lithuanians cooperated against the Soviets, but soon the cooperation gave way to increasing hostility.{{sfn|Łossowski|1966|p=47}}{{Sfn|Balkelis|2018|pp=137-138}} Lithuania claimed [[neutral country|neutrality]] in the Polish–Soviet War. As the Polish Army forced its way further into Lithuania, the first clashes between Polish and Lithuanian soldiers occurred on April 26 and May 8, 1919, near [[Vievis]].{{sfn|Lesčius|2004|p=252}} Though there was no formal state of war and few casualties, by July newspapers reported increasing clashes between Poles and Lithuanians, primarily around the towns of [[Merkinė]] and [[Širvintos]].{{sfn|Łossowski|1966|p=48}} Direct negotiations in Kaunas between May 28 and {{awrap|June 11}}, 1919, collapsed as neither side agreed to compromise. Lithuania tried to avoid direct military conflict and submitted its case for mediation to the Conference of Ambassadors.{{sfn|Łossowski|1966|p=49}}

In the [[Suwałki Region|Suwałki region]], Lithuanian troops, supported by German troops, were advancing in a southerly direction. The entire region was under the control of the German army, which allowed in the southern part to organize Polish administrations and to hold elections to the Polish Sejm in the counties of [[Augustów]], [[Suwałki]] and [[Sejny]]. However, at the same time, they allowed the formation of Lithuanian administrations in the northern part.{{Sfn|Łossowski|1996|p=50}} Lithuanians controlled Sejny from mid-1918, and entered Suwałki on May 8, 1919.{{Sfn|Łossowski|1996|p=40}}

=== Diplomatic developments ===
While still World War I was still ongoing, under German tutelage, the two sides established diplomatic ties, signing an agreement in Berlin on 30 June 1918.<ref name=":1">{{Cite journal |last=Lopata |first=Raimundas |date=1993 |title=Lithuanian-Polish cooperation in 1918: The Ronikier-Voldemaras treaty |url=https://www.tandfonline.com/doi/abs/10.1080/01629779300000241 |journal=Journal of Baltic Studies |language=en |volume=24 |issue=4 |pages=349–358 |doi=10.1080/01629779300000241 |issn=0162-9778}}</ref> Lithuania was represented by [[Augustinas Voldemaras]] and [[Konstantinas Olšauskas]], while Poland was represented by [[Adam Ronikier]].<ref name=":1" /> Both sides recognized each other's statehood.{{Sfn|Senn|1966|p=13-14}} In the treaty, Lithuania guaranteed the rights of the Polish minority, while Poland promised to refrain from anti-Lithuanian propaganda.{{sfn|Lopata|1993|pp=351-352, 356}} Voldemaras later maintained that Ronikier renounced Polish claims to Vilnius.{{sfn|Lopata|1993|p=349}} However, [[Alfred E. Senn]] wrote that the issue of the border and the belonging of Vilnius was not addressed in the treaty,{{Sfn|Senn|1966|p=13-14}} while according to [[Pranas Čepėnas]] and {{Interlanguage link|Wiktor Sukiennicki|pl}} the signed agreement mentioned nothing regarding territorial questions.{{sfn|Lopata|1993|p=349}} The treaty (published in full by {{Interlanguage link|Raimundas Lopata|lt}}) was of interim nature and stated only that: "With regard to the frontier, a principle of a common frontier is accepted, which will be determined by a joint agreement based on ethnic, historic and economic principles".{{sfn|Lopata|1993|p=356}} After the Germans had withdrawn, the Lithuanian side pressed for Poland's recognition of an independent Lithuania with its capital in Vilnius, which the Polish leadership consistently rejected.{{sfn|Lane|2001|p=7}}

Polish leader Józef Piłsudski hoped to revive the old [[Polish–Lithuanian Commonwealth]] (see the [[Intermarium]] federation) and campaigned for some kind of Polish–Lithuanian union in the [[Paris Peace Conference (1919–1920)|Paris Peace Conference]].{{sfn|Lane|2001|p=7}} Oppositional [[Endecja]] desired Lithuania's annexation to Poland,{{Sfn|Balkelis|2018|p=52}} with granting Lithuanians territorial autonomy within ethnic boundaries.<ref name="Engelgard" /> Poland also did not intend to make any territorial concessions and justified its actions not only as part of a military campaign against the Soviets but also as the right of self-determination of local Poles.{{Sfn|Eidintas|Žalys|Senn|1999|p=72}} Due to Polish–Lithuanian tensions, the [[Allies of World War I|Allied Powers]] withheld diplomatic recognition of Lithuania until 1922.<ref name="salzmann" />

The Lithuanians claimed Vilnius as their historical capital and refused any federation with Poland, desiring an independent Lithuanian state. They regarded Polish federalism as a recreation of Polish cultural and political dominance.{{sfn|Lane|2001|p=7}} The Lithuanian government in [[Kaunas]], designated as the [[temporary capital of Lithuania|temporary capital]], deemed the Polish presence in Vilnius as an illegal occupation.<ref name="bojtar" /> In addition to the Vilnius Region, the Suwałki Region was also disputed. It had a mixed Polish and Lithuanian population.<ref name="suziedelis" />

At the time the international situations of newly independent Poland and Lithuania were unequal. Poland, much larger in territory and population, was dedicated point #13 in [[Woodrow Wilson]]'s [[Fourteen Points]]. It was recognized by all nations of the Entente, officially invited to the [[Paris Peace Conference, 1919|Paris Peace Conference]], and became one of the founding members of the [[League of Nations]].{{sfn|Gerutis|1984|p=166}} Poland also enjoyed a close [[Franco-Polish alliance|alliance with France]].

Lithuania did not receive international recognition (it was first recognized ''de jure'' in July 1920 by [[Russian Soviet Federative Socialist Republic|Soviet Russia]] as part of the peace treaty) as the Entente hoped to revive the Russian Empire within its former territory, which included Lithuania.{{sfn|Vilkelis|2006|p=57}} Lithuania was looking for support in [[Weimar Republic|Germany]] and Russia. In Paris, Voldemaras made contact with Russian delegates to the Paris Conference, who resented an independent Poland and were also interested in limiting its influence in the east and blocking a Polish-Lithuanian agreement. However, they had no real power in Russia, besides that they themselves considered Lithuania part of Russia, so no agreement was reached.{{Sfn|Łossowski|1996|p=37}} Contacts with the Germans were much more fruitful. Germany realized that France was interested in a strong Polish ally east of Germany. So, for their part, they supported the building of Lithuania, which would be unfriendly to Poland. Threatened from both sides, the Lithuanian government turned to Germany for military and financial assistance.{{Sfn|Łossowski|1996|p=38}} German troops remained in Kaunas in early 1919, and the government was supported by German loans.{{Sfn|Senn|1966|p=15, 17}} The military presence in Lithuania also gave Germany cover for East Prussia and the ability to control the situation in Russia.{{Sfn|Łossowski|1996|p=37}}

The Lithuanian delegation was also present at the Paris Peace Conference, where its leader Augustinas Voldemaras focused on receiving recognition of independent Lithuania and its borders. Voldemaras demanded 125,000 square kilometers for Lithuania, not only with Vilnius but also [[Suwałki]] and [[Białystok]]. He also accused Poland of being partitionist, and portrayed Poland as an anti-Semitic state that was a threat to [[Lithuanian Jews]].<ref name="Engelgard">{{Cite journal |last=Engelgard |first=Jan |date=2010 |title=Litwa w polityce Komitetu Narodowego Polskiego w latach 1917-1919 |url=https://bazhum.muzhp.pl/media/files/Niepodleglosc_i_Pamiec/Niepodleglosc_i_Pamiec-r2010-t17-n1_(31)/Niepodleglosc_i_Pamiec-r2010-t17-n1_(31)-s57-64/Niepodleglosc_i_Pamiec-r2010-t17-n1_(31)-s57-64.pdf |journal=Niepodległość i Pamięć |volume=17 |issue=1 |pages=59}}</ref> On the other hand, Voldemaras battled negative propaganda that the [[Council of Lithuania]] was a German puppet, that Lithuanians harboured pro-Bolshevik attitudes,{{sfn|Gerutis|1984|p=166}} or that Lithuania was too small and weak to survive without a union with Poland.{{sfn|Vilkelis|2006|p=58}} Under article 87 of the [[Versailles Treaty]], the [[Principal Allied Powers]] reserved to themselves the right to determine Poland's eastern frontier.<ref>{{cite book |last1=Rozek |first1=Edward J. |title=Wartime Diplomacy: A Pattern In Poland |date=1989 |publisher=[[Westview Press]] |isbn=0813378990 |page=18}}</ref><ref>{{cite book |last1=Lojkó |first1=Miklós |title=Meddling in Middle Europe: Britain and the 'Lands Between' 1919-1925 |date=2005 |publisher=[[Central European University Press]] |isbn=9789637326370 |page=259}}</ref>

The war situation and the unstable political situation in both countries did not facilitate contacts between the two governments. Lithuanians protested the presence of Polish troops on Lithuanian territory in early January 1919, but the information reached Warsaw when Vilnius was already in Bolshevik hands. The Poles responded on February 12 by rejecting Lithuanian demands for lands they considered their own, but offered to open direct diplomatic talks. The Lithuanian delegation reached Warsaw on April 18, a day before the entrance of Polish troops to Vilnius.{{Sfn|Senn|1966|p=18-19}}

Meanwhile, [[Michał Pius Römer|Michal Römer]], a Lithuanian patriot and veteran of [[Polish Legions in World War I|Polish Legions]] under Piłsudski, went to Kaunas on a mission, and was expected to convince Lithuanian politicians of federation. However, he only found understanding among Lithuanians of Polish culture.{{Sfn|Łossowski|1996|p=40}} On April 17, Lithuanian politicians categorically rejected the federation's proposals.{{Sfn|Łossowski|1996|p=40}}

The Lithuanian delegation, led by [[Jurgis Šaulys]], held talks with Polish Prime Minister [[Ignacy Jan Paderewski]] on May 13 and 23, and with Polish Head of State [[Józef Piłsudski]] on May 21.{{Sfn|Senn|1966|p=19}} The Polish side, strengthened by its possession of Vilnius, insisted on the establishment of a federation, with a common foreign policy, army command, railroad, treasury and post office, promising to establish borders favorable to Lithuania.{{Sfn|Łossowski|1996|p=39}} The Lithuanian side, on the other hand, demanded recognition of an independent Lithuania with Vilnius as its capital.{{Sfn|Łossowski|1996|p=39}} The talks failed, with the only result being the establishment of a Lithuanian consulate in Warsaw, headed by {{Ill|Antanas Kasakaitis|lt}}.{{Sfn|Łossowski|1996|p=40}}

== May–September 1919: rising tensions ==
=== Demarcation lines ===
The Conference of Ambassadors drew the first [[demarcation line]] on June 18, 1919.{{Sfn|Eidintas|Žalys|Senn|1999|p=71}} The line, drawn about {{convert|5|km|abbr=on}} west of the [[Saint Petersburg–Warsaw railway|Grodno–Vilnius–Daugavpils Railway]], was based on the military situation on the ground rather than ethnic composition.{{Sfn|Eidintas|Žalys|Senn|1999|p=71}}{{sfn|Łossowski|1966|pp=49–50}} Neither Poles nor Lithuanians were content with the line. The Polish Ministry of Foreign Affairs rejected the line as it would require the Polish forces to retreat up to {{convert|35|km|abbr=on}}.{{sfn|Łossowski|1966|pp=49–50}} The line also left the entire [[Suwałki Region|Suwałki region]], with exception of [[Augustów]], on the Lithuanian side.{{Sfn|Łossowski|1996|p=40}} The Lithuanians protested leaving Vilnius and [[Hrodna|Grodno]] under Polish control.{{sfn|Łossowski|1966|pp=49–50}} As German volunteers were departing from Lithuania and Lithuanian forces were preoccupied with battles against the Soviets in northern Lithuania, Poland ignored the demacration line and moved its forces on a {{convert|100|km|abbr=on|adj=on}} wide front {{convert|20|–|30|km|abbr=on}} deeper eastward.{{sfn|Lesčius|2004|p=254}}

On July 18, [[Ferdinand Foch]] proposed the second demarcation line, known as the [[Foch Line]].<ref name=manczuk/> It was approved by the Entente on July 26. The Lithuanians were informed about the new line only on August 3.{{Sfn|Senn|1975|p=134}} Two major modifications favorable to the Poles were made: the Suwałki Region was assigned to Poland and the entire line was moved about {{convert|7|km|abbr=on}} west.{{sfn|Lesčius|2004|pp=254, 257}} Again, both Poles and Lithuanians protested the line as it would require them to withdraw their armies from the Vilnius and Suwałki Regions respectively. The German administration, which had not yet retreated from the Suwałki Region, also opposed the Foch Line.{{sfn|Łossowski|1966|p=51}} The new line did not immediately halt the hostilities. After a couple of Polish attacks on July 29 and August 2, the front stabilized.{{sfn|Lesčius|2004|p=258}}

=== Sejny Uprising ===
{{main|Sejny Uprising}}
The Lithuanians retreated from Suwałki on August 7, 1919.{{sfn|Lesčius|2004|p=272}} However, they stopped in ethnically mixed [[Sejny]] and formed a line on the [[Czarna Hańcza]] River – [[Wigry Lake]].<ref name=BuchSt/> They showed their intention to stay there permanently, which caused concern among the local Poles. On August 12, they organized a rally in Suwałki demanding incorporation into Poland.<ref name=BuchSt/> Lithuanians also held a rally in Kaunas on August 17 protesting the Foch line, and a similar rally was later held in Sejny, where Prime Minister [[Mykolas Sleževičius]] arrived.{{Sfn|Łossowski|1996|p=67}}

The Sejny branch of [[Polish Military Organisation]] (PMO) began preparing for an uprising, scheduled for the night of August 22 to 23, 1919, right after German troops left the city. Between 900<ref name="BuchSt" /> and 1,200 partisans<ref name="manczuk" /> joined PMO forces. On August 23, the Poles captured Sejny and attacked [[Lazdijai]] and [[Kapčiamiestis]], towns on the Lithuanian side of the Foch Line.<ref name="BuchSt" /> The insurgents planned to march as far as [[Simnas]].<ref name="manczuk" /> Lithuanians recaptured Sejny on August 25 for a few hours. On August 26, regular Polish forces – the {{Ill|41st Infantry Regiment (Poland)|lt=41st Infantry Regiment|pl|41 Suwalski Pułk Piechoty}} – joined the PMO volunteers.<ref name="manczuk" /> On September 5, the Lithuanians agreed to withdraw behind the Foch Line by September 7.{{sfn|Lesčius|2004|p=277}} Poland secured Sejny and repressed Lithuanian cultural life: the [[Sejny Priest Seminary]] was expelled, Lithuanian schools and cultural organizations closed.<ref name="BuchKr" /> After the uprising, the mistrust of Poles prompted Lithuanian intelligence to intensify its investigations of Polish activities in Lithuania. This helped to detect and prevent a planned [[coup d'état]] in Kaunas to overthrow the government of Lithuania.<ref name="manczuk" />

=== Polish coup attempt ===
{{main|1919 Polish coup d'état attempt in Lithuania}}
Sometime in mid-July 1919,{{sfn|Lesčius|2004|p=261}} PMO forces in Vilnius began planning a coup to replace the Lithuanian government with a pro-Polish cabinet, which would agree to a union with Poland (the proposed [[Międzymorze]] federation). Polish leader Józef Piłsudski believed there were enough Polish sympathizers in Lithuania to carry out the coup.<ref name=manczuk/> On August 3, a Polish diplomatic mission, led by [[Leon Wasilewski]] and [[Tadeusz Kasprzycki]], in Kaunas had a double purpose: propose a [[plebiscite]] in the contested territories{{sfn|Łossowski|1966|pp=56–57}} and assess preparedness for the coup.{{sfn|Senn|1966|p=20}} On August 6, the Lithuanian government rejected the plebiscite proposal, stating that the disputed territories constitute [[ethnographic Lithuania]].{{sfn|Łossowski|1966|pp=56–57}} According to Lithuanian historian [[Kazys Ališauskas]], PMO planned to capture and hold Kaunas for a few hours until the arrival of the regular Polish troops, situated only some {{convert|40|–|50|km|abbr=on}} east from the city.{{Sfn|Ališauskas|1968|p=101}} Piłsudski and his entourage were sincerely convinced that [[Taryba]], who ruled Lithuania, had no real popular support and was merely a German creation. They were bolstered in this conviction by intra-Lithuanian quarrels, primarily between Lithuanian émigré leader [[Juozas Gabrys]] and newly elected President [[Antanas Smetona|Smetona]], who lacked democratic legitimacy. This conviction was reinforced by the constant presence of the German army in Lithuania.{{Sfn|Łossowski|1996|p=56-59}} The Germans' departure from Kaunas on July 11, 1919, created the conditions for military action.{{Sfn|Łossowski|1996|p=56}} Polish newspapers ran a propaganda campaign claiming that the [[Council of Lithuania]] was simply a German puppet.{{sfn|Senn|1975|p=148}}

It managed to win the support of some Lithuanian politicians, most notably the aforementioned Gabrys, Defense Ministry employee Jurgis Aukštuolaitis, and even Lithuanian army commander Silvestras Žukauskas. However, it was not much, greater success was achieved in gaining the support of Kaunas Poles.{{Sfn|Łossowski|1996|p=60-64}} The coup was initially scheduled for the night of August 27 to 28 but was postponed to September 1.{{sfn|Lesčius|2004|p=267}} The outbreak of the Sejny uprising, which reinforced resentment against Poles in Lithuania, further hindered the success of the coup.{{Sfn|Łossowski|1996|p=68-70}}

The postponement of the start of the coup turned out to be a fatal mistake, as some PMO units did not receive information about it and began operations on the original date, disrupting telegraph connections between Kaunas and the rest of the country.{{Sfn|Łossowski|1996|p=68-70}} Lithuanian intelligence discovered the coup, but did not have a list of PMO members. Lithuanian authorities began mass arrests of some 200 Polish activists, including 23 officers of the Lithuanian Army.{{sfn|Lesčius|2004|p=268}}{{Sfn|Łossowski|1996|p=72}} Kaunas was declared in a [[state of siege]]. Polish press saw mass arrests of Polish activists "to whom no charge can be ascribed other than being Poles" as proof of systematic anti-Polish policies of the German-ridden Lithuanian government.{{Sfn|Senn|1975|p=149}} Another wave of arrests took place on September 9 in Kaišiadorys, an important railroad junction, where about 100 people were arrested.{{Sfn|Łossowski|1996|p=75}} The PMO was little affected by the arrests and scheduled another coup attempt for the end of September. However, the Lithuanians obtained a full list of PMO members, including 369 names of members and 122 names of Lithuanians sympathetic to the PMO, and liquidated the organization in Lithuania.{{sfn|Lesčius|2004|pp=269–270}}{{Sfn|Łossowski|1996|p=77}} The wave of arrests, included names outside the list, Lithuanian police used this as a pretext to arrest Polish activists, there were even murders.{{Sfn|Łossowski|1996|p=77}}

== September 1919 – June 1920: minor incidents ==

=== Military developments ===
After the failure of the coup in Kaunas, there were numerous small border incidents. On September 17 and 18, Lithuanian troops attacked and occupied Musninkai and Širvintos, and were soon driven from them.{{Sfn|Łossowski|1996|p=95}} On September 19, 1919, Polish troops attacked [[Gelvonai]] and encroached towards [[Ukmergė]].{{sfn|Lesčius|2004|pp=280–281}} On several occasions fights broke out regarding a strategically important bridge over the [[Šventoji River]] near [[Vepriai]].{{sfn|Lesčius|2004|p=280}} In October, when main Lithuanian forces were deployed against the [[Bermontians]] in northwestern Lithuania, the attacks intensified. Poles captured [[Salakas]] on October 5{{Sfn|Ališauskas|1968|p=101}} and attacked [[Kapčiamiestis]] on October 12.{{sfn|Lesčius|2004|p=277}} When Polish troops were engaged in combat with Soviet forces German troops attacked Alanta on {{awrap|January 11,}} 1920, and Stakliškės on January 14.{{Sfn|Łossowski|1996|p=96}} The front stabilized, but harassment of border guards and local villagers continued throughout early 1920.

In March 1920, fights erupted along the railroad stations in [[Kalkūni, Daugavpils Municipality|Kalkūni]] and [[Turmantas]].{{sfn|Lesčius|2004|p=284}}{{Sfn|Łossowski|1996|p=98}} The situation was investigated by British and French observers and reported to the Entente. The situation somewhat improved only in late spring 1920, when most Polish troops were deployed in Ukraine during the {{awrap|Polish–Soviet War.{{Sfn|Ališauskas|1968|p=101}}}}

At the time Lithuania faced a severe budget crisis – in 1919 its revenue was 72 million while expenses reached 190 million [[German mark]]s.<ref name="drilinga" /> While the government was struggling to obtain financial assistance and loans, deep cuts affected the army. Instead of increasing its armed forces to 40,000 men, Lithuania was forced to cut them to about 25,000.{{sfn|Lesčius|2004|pp=285, 287}}

=== Diplomatic developments ===
After the failed coup, Leon Wasilewski left Kaunas and settled in Vilnius. There he met twice, on September 15 and 24, with Lithuanian Foreign Minister [[Augustinas Voldemaras|Augustian Voldemaras]]. The talks concerned bilateral relations, the possibility of a plebiscite, and ended without any concrete agreements.{{Sfn|Łossowski|1996|p=82}} Wasilewski then began propaganda work involving Lithuanian activists Józef Albin Herbaczewski, priest Antanas Viskantas or Jurgis Aukštuolaitis, who had been released from prison, and published bilingual or Lithuanian-language press for this purpose.{{Sfn|Łossowski|1996|p=84-86}}

Meanwhile, British influence was increasing in the Baltic States, interested primarily in limiting German, but also French influence.{{Sfn|Łossowski|1996|p=86-87}} A British military mission was established in Kaunas, headed by Richard Barrington Ward. On September 19, 1919, along with 21 other British officers, General [[Frank Percy Crozier]] joined the newly established Lithuanian Army as an advisor to the General Staff. On September 25, 1919, the UK recognized the Lithuanian state de facto. The British also provided military equipment.{{Sfn|Łossowski|1996|p=86-87}}

[[Latvia]] fought against the [[West Russian Volunteer Army|German-Russian forces]] of [[Pavel Bermondt-Avalov]]. Latvia enjoyed the support of Poland. The fighting spread to Lithuania in October 1919. Poland offered to help, but the Lithuanians refused to allow passage through their territory. Fearing a Polish attack, Lithuania reached an agreement with the Bermontians and signed a truce on October 30, establishing the Tauragė-Šiauliai demacration line.{{Sfn|Łossowski|1996|p=90}} After the Latvian army breached the front, the Lithuanian army joined the counteroffensive. Later clashes were stopped by the intervention of an [[Allies of World War I|Entente]] representative, in order to not interrupt withdrawal of German troops. By December 15, all German forces were completely removed from Lithuania. At the same time, the plenipotentiary of the German government {{Ill|Ludwig Zimmerle|de}} was forced to leave Kaunas.{{Sfn|Łossowski|1996|p=91}} On December 30, a Polish-Latvian alliance was signed, resulting in a joint fight for the liberation of [[Daugavpils]], which was successful [[Battle of Daugavpils|on January 5, 1920]]. Lithuanian troops attempted an early entry into the city, but without success.{{Sfn|Łossowski|1996|p=93}}

In April 1920, Lithuania held its first parliamentary elections, among the constituencies established were cities outside the Lithuanian administration: Vilnius, [[Lida]], [[Grodno]] and [[Białystok]]. The Polish minority had limited opportunities for election campaigning, the only Polish newspaper was closed down, and as a result Poles received only 3 parliamentary seats.{{Sfn|Łossowski|1996|p=100}} [[Kazys Grinius]] became the new prime minister. On May 11, 1920, France recognized Lithuania de facto.{{Sfn|Łossowski|1996|p=101}} And on May 7, 1920, Lithuania began peace talks with Soviet Russia.{{Sfn|Łossowski|1996|p=101-102}}

== July 1920: Soviet advance and Polish retreat ==
=== Diplomatic developments ===
[[File:PL-RU war 1919 phase III.svg|thumb|300px|Advance of Soviet forces (red arrows) against Polish troops in June–August 1920]]
On 25 April 1920, the Polish army and the remnants of [[Ukrainian People's Republic|Ukrainian People's Army]] under [[Symon Petliura|Petliura]] launched the large-scale [[Kiev offensive (1920)|Kiev offensive]] following the [[Treaty of Warsaw (1920)|treaty of alliance]].<ref>{{Cite book |last=Smele |first=Jon |url=http://worldcat.org/oclc/953633099 |title=Historical dictionary of the Russian civil wars, 1916-1926 |year=2015 |isbn=978-1-4422-5280-6 |pages=1093 |publisher=Rowman & Littlefield |oclc=953633099}}</ref> Initially successful, the Polish Army started retreating after Russian counterattacks in early June 1920.{{Sfn|Snyder|2003|p=63}} Soon the Soviet forces began to threaten Poland's independence as they reached and crossed the Polish borders. On July 9, Polish Prime Minister [[Władysław Grabski]] asked the [[Allies of World War I|Allied Powers]] in the [[Spa Conference of 1920|Spa Conference]] for military assistance in the war with the Soviets.{{sfn|Lesčius|2004|p=289}} The conference proposed that the Polish forces would withdraw behind the [[Curzon Line]], the Soviet forces would stop {{convert|50|km|abbr=on}} to the east of the line, the Lithuanian forces would take control of Vilnius, and all other disputes would be settled via negotiations in London.{{Sfn|Eidintas|Žalys|Senn|1999|p=72}} Grabski opposed the transfer of Vilnius, but under the pressure of British Prime Minister [[Lloyd George]], agreed to the resolution on July 10.{{Sfn|Eidintas|Žalys|Senn|1999|pp=72–73}}

At the same time, the Soviets and Lithuanians negotiated the [[Soviet–Lithuanian Peace Treaty]], which was signed on July 12, 1920. Russia recognized Lithuanian independence and withdrew any territorial claims. The treaty drew the eastern border of Lithuania, which the Lithuanians continued to claim as their ''de jure'' state border until World War II. [[Vilnius Region]], including [[Braslaw]] (Breslauja), [[Hrodna]] (Gardinas), [[Lida]] (Lyda), and [[Vilnius]], was recognized to Lithuania.{{Sfn|Eidintas|Žalys|Senn|1999|p=69}} On August 6, after long and heated negotiations, Lithuania and Soviet Russia signed a convention regarding the withdrawal of Russian troops from the recognized Lithuanian territory.{{sfn|Lesčius|2004|p=297}} However, the troops began to retreat only after the Red Army suffered a heavy defeat in Poland.{{sfn|Lesčius|2004|p=298}}

=== Territorial changes ===
The Bolshevik forces reached Lithuanian territory on July 7, 1920, and continued to push the Polish troops.{{Sfn|Ališauskas|1968|p=101}} The Lithuanian Army moved to secure territories abandoned by the retreating Polish forces, reaching [[Turmantas]] on July 7, [[Tauragnai]] and [[Alanta]] on July 9, [[Širvintos]] and [[Musninkai]] on July 10, [[Kernavė]], [[Molėtai]], and [[Giedraičiai]] on July 11,{{sfn|Lesčius|2004|pp=289–290}} [[Maišiagala]] and [[Pabradė]] on July 13.{{sfn|Lesčius|2004|p=291}} On July 13, the Polish command decided to transfer Vilnius to the Lithuanians following the Spa conference's resolution.{{Sfn|Eidintas|Žalys|Senn|1999|p=73}} Lithuanians moved in, but their trains were stopped by Polish soldiers near Kazimieriškės.{{sfn|Lesčius|2004|p=291}} Polish soldiers didn't receive orders to let Lithuanian troops go through.{{Sfn|Balkelis|2018|p=144}} This delay meant that the Bolsheviks were the first to enter Vilnius on July 14. By the time the first Lithuanian troops entered the city on July 15, it was already secured by the Soviets.{{Sfn|Senn|1966|p=31}} Poland sought to have Russians in the city as it would create much fewer complications when the Polish Army counterattacked.{{Sfn|Senn|1966|p=31}} Despite the Peace Treaty, the Soviets did not intend to transfer the city to the Lithuanians.{{Sfn|Eidintas|Žalys|Senn|1999|p=73}} Indeed, there were indications that the Soviets planned a coup against the Lithuanian government in hopes to re-establish the [[Lithuanian Soviet Socialist Republic (1918–1919)|Lithuanian SSR]].{{Sfn|Snyder|2003|p=63}}{{sfn|Rauch|1970|p=101}}

Despite the setback in Vilnius, the Lithuanians continued to secure territories in the Suwałki Region. They took [[Druskininkai]] on July 17, [[Vištytis]], [[Punsk]], [[Giby]], and [[Sejny]] on July 19, Suwałki on July 29,{{sfn|Lesčius|2004|p=298}} Augustów on August 8.{{sfn|Lesčius|2004|p=299}} The Polish units, afraid of being surrounded and cut off from the main Polish forces, retreated towards [[Łomża]]. The Lithuanian authorities started to organize themselves in the regained areas.{{sfn|Lesčius|2004|p=299}}

=== Lithuanian neutrality ===
Poland claimed that Lithuania violated its claim to neutrality in the Polish–Soviet War and in effect became a Soviet ally.{{Sfn|Senn|1966|p=32}} A secret clause of the Soviet–Lithuanian Peace Treaty allowed Soviet forces unrestricted movement within the Soviet-recognized Lithuanian territory for the duration of Soviet hostilities with Poland.{{Sfn|Snyder|2003|p=63}} This clause was of a practical matter: Soviet troops already occupied much of the assigned territory and could not withdraw while hostilities with Poland continued.<ref name=cepenas355/> Lithuanians were also simply unable to resist Soviet troops.{{Sfn|Senn|1966|p=40}} For example, when Lithuanians refused permission to use a road, the Soviets ignored Lithuanian protests and transported their troops and equipment regardless.{{sfn|Lesčius|2004|p=297}} At the same time Polish soldiers were disarmed and interned. The largest group, a brigade under colonel Pasławski, was interned on July 18, 1920, near [[Kruonis]].{{sfn|Lesčius|2004|pp=292–293}} On August 10, Lithuanians held 103 Polish officers and 3,520 private soldiers.{{sfn|Lesčius|2004|p=299}} Poland also claimed that the Lithuanian troops actively participated in the Red Army's military operations.<ref name=eudin/> This charge, based on memoirs of Soviet officials, lacks evidence.{{Sfn|Senn|1966|p=33}} Further military clashes between Polish and Lithuanian troops in the Suwałki Region were interpreted by Poland to show that "the Lithuanian government has become an instrument of the Soviet government."{{Sfn|Senn|1966|p=37}} Lithuania responded that it was defending its borders.{{Sfn|Senn|1966|p=37}}

== August–October 1920: struggles for the Suwałki Region ==

=== Polish advance and Soviet retreat ===
[[File:Suwalszczyzna.png|thumb|300px|Map of the Suwałki Region. Its many forests and lakes complicated the military actions.]]
The Russians suffered a great defeat in the [[Battle of Warsaw (1920)|Battle of Warsaw]] in mid-August 1920 and started withdrawing. They handed over Vilnius to the Lithuanians on August 26.{{Sfn|Eidintas|Žalys|Senn|1999|p=73}} The Lithuanians hastily made preparations to secure the border, as determined by the Soviet–Lithuanian Peace Treaty. The soldiers were ordered to maintain neutrality: avoid hostilities and [[Internment|intern]] any Soviet or Polish troops that would cross the border.{{sfn|Lesčius|2004|p=301}} On August 26, a Polish delegation, led by Colonel [[Mieczysław Mackiewicz]], arrived in Kaunas to negotiate the situation.{{sfn|Lesčius|2004|p=304}} The Poles, lacking authority to discuss political issues, were concerned with military aspects. They sought permission to transport Polish troops through the territory of Lithuania, wanted access to a portion of the [[Saint Petersburg–Warsaw railway]], and demanded that the Lithuanian troops would withdraw from the Suwałki Region behind the [[Curzon Line]].{{sfn|Lesčius|2004|p=304}} The Lithuanians refused to discuss military matters without a clear political Polish–Lithuanian border, that would be respected after the war.{{sfn|Lesčius|2004|p=304}} Due to these fundamental disagreements and Polish attacks, the negotiations broke down on August 30.{{sfn|Lesčius|2004|p=305}}

The Suwałki Region had strategic importance in the Polish–Soviet War. Following orders of [[Edward Rydz-Śmigły]], Polish forces took Augustów from Lithuanians in a surprise attack on August 28.{{sfn|Lesčius|2004|p=305}} Confused and disoriented, Lithuanians retreated from Suwałki and Sejny on August 30 and 31.{{Sfn|Ališauskas|1968|p=101}} The Lithuanians reorganized, gathered their forces (11 battalions with 7,000 soldiers),{{sfn|Lesčius|2004|p=307}} and organized a counterattack to retake lost territory on September 2.{{Sfn|Ališauskas|1968|p=101}} The goal was to take and secure the Augustów–[[Lipsk]]–[[Grabowo, Augustów County|Grabowo]]–[[Hrodna|Grodno]] line.{{Sfn|Ališauskas|1968|p=101}} The Lithuanians succeeded in re-taking Sejny and Lipsk and by September 4 reached the outskirts of Augustów.{{Sfn|Ališauskas|1968|p=101}} On September 5, the Poles counterattacked and forced the Lithuanians to retreat.{{sfn|Lesčius|2004|p=311}} On September 9, the Polish forces recaptured Sejny,<{{sfn|Lesčius|2004|p=314}} but the Lithuanians pushed back and regained Sejny and Giby on September 13 and 14.{{sfn|Lesčius|2004|p=317}} Pending direct negotiations, hostilities were ceased on both sides.{{sfn|Lesčius|2004|p=318}}

=== Direct negotiations and League of Nations ===
[[File:BnN 2.png|thumb|300px|Map of the [[Battle of the Niemen River]]: Polish forces manoeuvred through the Lithuanian front line (in pink) to the rear of Soviet troops]]
On September 6, Lithuanian Foreign Minister [[Juozas Purickis]] proposed direct negotiations in [[Marijampolė]].{{sfn|Lesčius|2004|pp=319–321}} On September 8, during a planning meeting of the [[Battle of the Niemen River]], the Poles decided to manoeuvre through the Lithuanian-held territory to the rear of the Soviet Army, stationed in Grodno.{{Sfn|Vilkelis|2006|p=66}} In an attempt to conceal the planned attack, Polish diplomats accepted the proposal to negotiate.{{Sfn|Vilkelis|2006|p=66}} The negotiations started on September 16 in [[Kalvarija, Lithuania|Kalvarija]], but collapsed just two days later.{{Sfn|Ališauskas|1968|p=102}}

On September 5, 1920, Polish Foreign Minister [[Eustachy Sapieha]] delivered a diplomatic note to the [[League of Nations]] alleging that Lithuania violated its neutrality and asked to intervene in the Polish–Lithuanian War.{{Sfn|Vilkelis|2006|p=64}}{{sfn|Senn|1966|pp=36–37}} The League agreed to mediate and began its session on September 16. The resolution, adopted on September 20, urged both states to cease hostilities and adhere to the Curzon Line.{{Sfn|Vilkelis|2006|p=67}} Poland was asked to respect Lithuanian neutrality if Soviet Russia agreed to do the same. Also, a special Control Commission was to be dispatched to the conflict zone to oversee the implementation of the resolution.{{sfn|Lesčius|2004|p=320}} It was clear that the League had only a narrow goal to prevent armed hostilities and not to resolve the underlying territorial dispute.{{Sfn|Senn|1966|p=40}}{{Sfn|Eidintas|Žalys|Senn|1999|p=74}} The Lithuanian government accepted the resolution, but Poland reserved full freedom of action in preparation for the attack on the Soviets.{{sfn|Lesčius|2004|p=321}}{{Sfn|Vilkelis|2006|p=68}}

=== Battle of the Niemen River ===
{{main|Battle of Sejny}}
On September 22, 1920, Poland attacked Lithuanian units in the Suwałki Region on a wide front.{{Sfn|Eidintas|Žalys|Senn|1999|p=74}} Overwhelmed by 4–5 times larger Polish forces,{{sfn|Lesčius|2004|p=324}} some 1,700{{Sfn|Vilkelis|2006|p=68}}–2,000{{sfn|Lesčius|2004|p=330}} Lithuanian troops surrendered and were taken prisoner.

Polish forces then marched, as planned on September 8, across the [[Neman River]] near [[Druskininkai]] and [[Merkinė]] to the rear of the Soviet forces near Grodno and Lida.{{sfn|Borzęcki|2008|p=106}} The Red Army hastily retreated. The Lithuanians had had limited intelligence warning that such an attack might occur,{{sfn|Lesčius|2004|p=324}} but chose an inadequate defensive strategy and spread their forces too thinly along the entire Polish–Lithuanian front{{sfn|Lesčius|2004|p=330}} without sufficient forces to protect the bridges across the Neman.{{sfn|Lesčius|2004|p=329}} This attack, just two days after the resolution by the League of Nations to cease hostilities, put more pressure on Poland to settle the dispute peacefully.{{Sfn|Vilkelis|2006|p=69}}

On September 26, the Poles captured Grodno{{sfn|Borzęcki|2008|p=106}} and the Polish foreign minister proposed new negotiations in Suwałki.{{sfn|Lesčius|2004|p=344}} The Battle of the Niemen River drastically altered the balance of power: Vilnius, in Lithuanian hands since August 26, was now exposed to a Polish attack.{{Sfn|Vilkelis|2006|p=70}} Indeed, the Poles had already decided to capture the city and used the negotiations in Suwałki to stall and buy the time necessary to make preparations.{{Sfn|Vilkelis|2006|pp=70–71}}{{sfn|Senn|1966|p=44}} The Lithuanian side was ready to give up the Suwałki Region in exchange for Poland's recognition of the Lithuanian claims to Vilnius.<ref name=los166-175/>

=== Suwałki Agreement ===
{{main|Suwałki Agreement}}
[[File:Border-Lithuania-Poland-1919-1939.svg|thumb|300px|Selected demarcation lines between Poland and Lithuania. The line drawn by the Suwałki Agreement is in yellow; the final interwar border is in red.]]
The negotiations between Poles, led by [[Pułkownik|colonel]] [[Mieczysław Mackiewicz]], and Lithuanians, led by [[Lieutenant General|general]] [[Maksimas Katche]], began on the evening of September 29, 1920.<ref name=los166-175/> Both sides agreed to an [[armistice]] but only to the west of the Neman River (the Suwałki Region).{{sfn|Lesčius|2004|p=345}} Fighting to the east of the river continued around [[Marcinkonys]], [[Zervynos]], [[Perloja]], [[Eišiškės]].{{sfn|Lesčius|2004|pp=336–339}} The major point of contention, both diplomatic and military, was the train station in [[Varėna]] (Orany) on the [[Saint Petersburg–Warsaw railway]]. Major Lithuanian forces were still concentrated in the Suwałki Region and moving them to protect Vilnius without the railway would be extremely difficult.{{sfn|Lesčius|2004|p=345}} Fighting east of the Neman River ceased only on October 6, when Polish troops had already captured the train station in Varėna.{{Sfn|Ališauskas|1968|p=102}}

Negotiations regarding the demarcation line were difficult. In essence, the Lithuanians wanted a longer demarcation line to provide better protection for Vilnius. The Poles agreed only to a short line to provide the planned attack on Vilnius with space for operation.{{Sfn|Vilkelis|2006|p=71}} The Polish delegation was also stalling to buy time for necessary preparations for an attack on Vilnius.{{Sfn|Vilkelis|2006|pp=70–71}}{{sfn|Lesčius|2004|p=345}} While Vilnius was not a topic of debate, it was on everybody's mind.{{Sfn|Eidintas|Žalys|Senn|1999|p=74}} On October 4, the Control Commission, sent by the League according to its resolution of September 20, arrived to Suwałki.{{Sfn|Vilkelis|2006|p=68}} The commission, led by French colonel Pierre Chardigny, re-energized the negotiations.{{Sfn|Vilkelis|2006|p=71}} On October 7, at midnight,{{Sfn|Vilkelis|2006|p=71}} the final agreement was signed. The treaty made not a single reference to Vilnius or the Vilnius Region.<ref name=untc/> The ceasefire was effective only along the demarcation line, which ran through the Suwałki Region to the train station in {{ill|Bastuny|pl|lt=Bastuny.}}<ref name=untc/> Thus the line was incomplete, did not protect the Vilnius Region,{{Sfn|Eidintas|Žalys|Senn|1999|p=75}} but indicated it would be left on the Lithuanian side.{{sfn|Lane|2001|p=31}}

== October–November 1920: struggles for Vilnius Region ==
=== Żeligowski's Mutiny ===
{{main|Żeligowski's Mutiny}}
[[File:Rzeczpospolita Central Lithuania.png|thumb|300px|Map of the [[Republic of Central Lithuania]] (in green)]]
Polish chief of state Józef Piłsudski ordered his subordinate, General [[Lucjan Żeligowski]], to stage a mutiny with his [[1st Lithuanian–Belarusian Division]] (16 battalions with 14,000 soldiers){{sfn|Lesčius|2004|pp=349–350}} in [[Lida]] and capture Vilnius in ''[[fait accompli]]''. The rebellion had two main goals: capture Vilnius and preserve Poland's international reputation. The League of Nations was mediating other Polish disputes, notably over the [[Free City of Danzig]] and [[Upper Silesia]], and direct aggression against Lithuania could have hampered Polish bargaining positions.{{Sfn|Vilkelis|2006|p=75}} While the Polish side officially held Żeligowski to be a deserter and did not support him,{{sfn|Rauch|1970|p=101}} Poland provided logistic support, including munitions and food rations,{{sfn|Lesčius|2004|p=377}} to his units.<ref name=loss1991/><ref name=cepenas/> Żeligowski also received reinforcements, when, according to the official version, the mutiny spread further among the Polish troops.{{Sfn|Ališauskas|1968|p=102}}{{sfn|Lesčius|2004|p=260}} His initial attack was secured on both sides by two Polish Armies.{{sfn|Borzęcki|2008|p=140}}

[[Żeligowski's Mutiny]], in planning since mid-September,{{Sfn|Vilkelis|2006|p=69}} began in the early morning of October 8, 1920, just a few hours after the signing of the Suwałki Agreement.{{sfn|Lesčius|2004|p=351}} A provisional agreement was made in the Polish–Soviet War, which freed up Polish units for the attack on Lithuania.{{Sfn|Eidintas|Žalys|Senn|1999|p=75}} As part of the ruse, Żeligowski wrote a note to the Polish command announcing his mutiny and expressing his disappointment with the Suwałki Agreement.{{sfn|Lesčius|2004|p=351}} He claimed that his troops marched to defend the right of [[self-determination]] of the local Polish population.{{sfn|Lesčius|2004|p=351}}

=== Capture of Vilnius and other military attacks ===
{{main|Central Lithuanian offensive of November 1920}}
The Lithuanians were not prepared for the assault. They had only two battalions, stationed near [[Jašiūnai]] and {{ill|Rūdninkai|lt}} along the [[Merkys River]], shielding the city from Poland.{{Sfn|Ališauskas|1968|p=102}} Their main forces were still in the Suwałki Region and to the west from [[Druskininkai]] and [[Varėna]]. Without the railway, Lithuanian units could not be easily redeployed to protect Vilnius.{{Sfn|Eidintas|Žalys|Senn|1999|p=75}} After it became clear that Żeligowski would not stop in Vilnius, Commander of the Lithuanian Army [[Silvestras Žukauskas]], who had recently taken the position on October 6, ordered the city evacuated in the afternoon on October 8.{{Sfn|Ališauskas|1968|p=102}} They left the city's administration to Entente official Constantin Reboul.{{sfn|Lesčius|2004|p=355}} The first Polish units entered the city around 2:15 PM on October 9, Żeligowski entered Vilnius in the evening the same day.{{sfn|Wyszczelski|2008|p=261}}{{efn|"On 9 October 1920 Żeligowski marched about 15,000 troops into Wilno. The Lithuanian army offered no resistance, and the city’s Polish population welcomed the troops."{{Sfn|Snyder|2003|p=64}}}} He did not recognize Reboul's authority and Entente officials left the city in protest.{{sfn|Lesčius|2004|p=357}} On October 12, Żeligowski proclaimed the independence of the [[Republic of Central Lithuania]], with Vilnius as its capital.{{Sfn|Snyder|2003|p=64}} The name aligned with Piłsudski's vision of historical Lithuania, divided into three cantons: Lithuanian-inhabited Western Lithuania with its capital in [[Kaunas]], Polish-inhabited Central Lithuania with its capital in Vilnius, and Belarusian-inhabited Eastern Lithuania with its capital in [[Minsk]].{{Sfn|Snyder|2003|p=64}} Further developments of other cantons were prevented by [[National Democracy (Poland)|Polish National Democracy]], a party opposed to Piłsudski's federalist ideas.{{Sfn|Snyder|2003|p=64}}

Żeligowski's units continued to advance: territories east of the city were taken without resistance{{sfn|Lesčius|2004|p=365}} while Lithuanians defended in the west. Żeligowski took [[Švenčionys]] and [[Rūdiškės]] on October 10, [[Nemenčinė]] on October 11, [[Lentvaris]] on October 13, [[Rykantai]] on October 15.{{Sfn|Ališauskas|1968|p=102}} The front somewhat stabilized on the southern (left) side of the [[Neris River]], but fighting continued on the northern (right) side of Neris.{{Sfn|Ališauskas|1968|p=103}} On October 18, the Lithuanian army began a failed counteroffensive trying to retake Vilnius.{{sfn|Wyszczelski|2008|p=269}} When Polish cavalry manoeuvred towards [[Riešė]], it learned from the local population the location of the command of the 1st Riflemen Division.{{sfn|Lesčius|2004|p=366}} On October 21, the cavalry raided the village and took the entire command (including [[Stasys Nastopka]]) prisoner. Left without their commanders, the Lithuanians retreated and Poles took [[Maišiagala]] and [[Paberžė]].{{sfn|Lesčius|2004|p=368}} Żeligowski at this point offered peace negotiations but was refused by the Lithuanian command.{{sfn|Wyszczelski|2008|p=269}} On October 26, another cavalry raid captured [[Dubingiai]], [[Giedraičiai]] and [[Želva]] and threatened [[Ukmergė]].{{sfn|Lesčius|2004|p=369}} However, Lithuanians counterattacked and took back Želva on October 30 and Giedraičiai on November 1. For a while, the front stabilized.{{Sfn|Ališauskas|1968|p=103}}

{{Main|October Offensive of the Central Lithuanian Army}}

On November 17, the mutineers began a major attack. They planned to capture Kaunas, thus threatening Lithuanian independence,{{Sfn|Eidintas|Žalys|Senn|1999|p=77}} by encircling the city from the north through [[Širvintos]]–Ukmergė–[[Jonava]] and Giedraičiai–[[Kavarskas]]–[[Kėdainiai]].{{Sfn|Ališauskas|1968|p=103}} Żeligowski's forces were about three times larger: 15 Polish battalions against 5 Lithuanian battalions.{{sfn|Lesčius|2004|pp=377–378}} One cavalry brigade managed to break through the Lithuanian defence lines near Dubingiai, reached Kavarskas, and continued towards Kėdainiai.{{Sfn|Ališauskas|1968|p=103}} However, Lithuanians successfully stopped an attack on Ukmergė near Širvintos on November 19. About 200 Lithuanians manoeuvred through swamps to the rear of three Polish battalions.{{sfn|Lesčius|2004|pp=385–386}} Attacked from the front and rear, some 200 Poles were taken prisoner while others retreated.{{sfn|Lesčius|2004|p=386}} The Lithuanians continued to attack and captured Giedraičiai on November 21. On the same day, a ceasefire was signed under pressure from the League of Nations.{{Sfn|Ališauskas|1968|p=104}} The Polish cavalry brigade, pushed from Kėdainiai and cut off from its main forces, retreated through [[Ramygala]]–[[Troškūnai]]–[[Andrioniškis]]–Leliūnai{{sfn|Lesčius|2004|pp=394–399}} and rejoined Żeligowski's other units only on November 24.{{Sfn|Ališauskas|1968|p=104}}

=== Mediation and diplomatic measures ===
On October 11, 1920, the Lithuanian envoy in Paris [[Oscar Milosz]] asked the League of Nations to intervene in the renewed conflict with Poland.{{Sfn|Vilkelis|2006|p=73}} On October 14, the Chairman of the League [[Léon Bourgeois]] issued a note condemning the aggression and asking Polish units to retreat.{{sfn|Vilkelis|2006|pp=73–74}} Politicians in London even considered expelling Poland from the League.<ref name=yearwood/> When the League heard both arguments on October 26–28, Polish envoy [[Szymon Askenazy]] claimed that there was no conflict between Poland and Lithuania to mediate.{{Sfn|Vilkelis|2006|pp=76–77}} He maintained that the old conflict ended with signing ceasefires with Lithuania on October 7 and with Soviet Russia on October 12 and the new conflict was caused by Żeligowski,{{Sfn|Vilkelis|2006|pp=76–77}} who acted without approval from the Polish command, but with the moral support of the entire Polish nation.{{Sfn|Eidintas|Žalys|Senn|1999|p=76}} Lithuanian envoy [[Augustinas Voldemaras]] argued that Poland orchestrated the mutiny and demanded strict sanctions against Poland.{{Sfn|Vilkelis|2006|p=77}} The League refused to validate Żeligowski's action.{{Sfn|Eidintas|Žalys|Senn|1999|p=76}} It suggested to hold a [[plebiscite]] in the contested areas. On November 6 and 7, both sides agreed{{Sfn|Vilkelis|2006|p=77}} and Lithuanians began preparatory work.{{Sfn|Vilkelis|2006|p=80}}

On November 19, Żeligowski proposed to the Control Commission, led by Chardigny, to cease hostilities.{{sfn|Lesčius|2004|p=402}} Lithuanians agreed and a ceasefire was signed on November 21. Later this episode was criticized by Lithuanian commentators as at the time the Lithuanian Army had the initiative in the front and had a chance of marching on Vilnius.{{Sfn|Eidintas|Žalys|Senn|1999|p=77}} However, the Lithuanians trusted the League of Nations would resolve the dispute in their favour{{Sfn|Vilkelis|2006|p=75}} and were afraid that in case of an attack on Vilnius regular Polish forces would arrive to reinforce Żeligowski's units.{{sfn|Lesčius|2004|p=403}}

Negotiations for a more permanent armistice, under the mediation of the Control Commission, began on November 27 in Kaunas.{{sfn|Lesčius|2004|p=403}} Lithuania did not agree to negotiate directly with Żeligowski and thus legitimizing his actions.{{Sfn|Eidintas|Žalys|Senn|1999|p=77}} Therefore, Poland stepped in as a mediator. Lithuania agreed as it hoped to put the talks back into the context of the [[Suwałki Agreement]].{{Sfn|Eidintas|Žalys|Senn|1999|p=78}} Poles rejected any withdrawal of Żeligowski's forces. No agreement could be reached regarding a demarcation line. On November 29, 1920, it was agreed only to cease hostilities on November 30, to entrust the Control Commission with the establishment of a {{convert|6|km|abbr=on|adj=on}} wide neutral zone and to exchange prisoners.{{sfn|Lesčius|2004|p=403}} The neutral zone existed until February 1923.{{Sfn|Ališauskas|1968|p=104}}

== Aftermath ==
[[File:Lithuanian newspaper Karys front page (October 1926).jpg|thumb|274x274px|right|Article in [[Karys]] titled "Hey, world! We will not rest without Vilnius!", 1926]]
The result of this war was that while Lithuania defended its independence against Poland and its puppet state [[Republic of Central Lithuania|Central Lithuania]], Lithuania also lost a third of its territory and its capital. The issue would not be laid to rest during the interwar as no peace treaty was ever signed, and [[Lithuania–Poland relations]] were broken off until the [[1938 Polish ultimatum to Lithuania]]. In 1920–1939, Lithuania and Poland were separated by a [[demarcation line]] that mostly followed the [[Foch Line]], which meant that [[Vilnius]] and [[Suwałki region]] were under Polish rule.

In March 1921, the plans for a plebiscite were abandoned. Neither Lithuania, which was afraid of a negative result nor Poland, which saw no reason to change ''[[status quo]]'', wanted the plebiscite.{{Sfn|Eidintas|Žalys|Senn|1999|p=78}} The parties could not agree on which territory to carry out the vote and how Żeligowski's forces should be replaced by League's forces.{{Sfn|Eidintas|Žalys|Senn|1999|p=78}} The League of Nations then moved on from trying to solve the narrow territorial dispute in the Vilnius Region to shaping the fundamental relationship between Poland and Lithuania. In 1921, Belgian [[Paul Hymans]] suggested several Polish–Lithuanian federation models, all rejected by both sides.{{sfn|Rauch|1970|p=102}} In January 1922, [[1922 Republic of Central Lithuania general election|parliamentary election to the Wilno Diet]] (''Sejm wileński'') resulted in a landslide Polish victory. In its first session on February 20, 1922, the Diet voted for incorporation into Poland as the [[Wilno Land]] and then [[Wilno Voivodeship (1926–1939)|Voivodeship]].{{Sfn|Eidintas|Žalys|Senn|1999|p=84}} Polish [[Sejm]] accepted the resolution of the Diet.{{Sfn|Eidintas|Žalys|Senn|1999|p=84}}<ref>[https://repozytorium.uni.wroc.pl/dlibra/publication/119330/edition/116538/content A. Srebrakowski, Sejm Wileński 1922 roku. Idea i jej realizacja, Wrocław 1993], [http://www.hist.uni.wroc.pl/pdf/srebrakowski/stosunek.pdf A. Srebrakowski, Stosunek mniejszości narodowych Litwy Środkowej wobec wyborów do Sejmu Wileńskiego]</ref> The League of Nations ended its efforts to mediate the dispute. After Lithuanians seized the [[Klaipėda Region]] in January 1923, the League saw recognition of Lithuanian interest in Klaipėda as adequate compensation for the loss of Vilnius.{{Sfn|Eidintas|Žalys|Senn|1999|p=85}} The League accepted the ''status quo'' in February 1923 by dividing the neutral zone and setting a demarcation line, which was recognised in March 1923 as the official Polish–Lithuanian border.{{Sfn|Eidintas|Žalys|Senn|1999|p=85}} Lithuania did not recognize this border.{{Sfn|Eidintas|Žalys|Senn|1999|p=85}}

Some historians, notably [[Alfred E. Senn]], have asserted that if Poland had not prevailed in the Polish–Soviet War, Lithuania would have been invaded by the Soviets and would never have experienced two decades of independence.<ref name="Senn" /> Despite the [[Soviet–Lithuanian Peace Treaty]] of 1920, Lithuania was very close to being invaded by the Soviets in the summer of 1920 and being forcibly incorporated into that state, and only the Polish victory derailed that plan.<ref name="Senn" />

The dispute over Vilnius remained one of the biggest foreign policy issues in Lithuania and Poland. Lithuania broke off all diplomatic relations with Poland and refused any actions that would recognize Poland's control of Vilnius even ''[[de facto]]''.<ref name="msn" /> For example, Lithuania broke off diplomatic relations with the [[Holy See]] after the [[Concordat of 1925]] established an ecclesiastical province in Wilno and thereby acknowledged Poland's claims to the city.{{sfn|Gerutis|1984|pp=218–219}} Poland refused to formally recognize the existence of any dispute regarding the region since that would have lent legitimacy to the Lithuanian claims.{{Sfn|Eidintas|Žalys|Senn|1999|p=146}} Railroad traffic and telegraph lines could not cross the border, and mail service was complicated. For example, a letter from Poland to Lithuania needed to be sent to a neutral country and repackaged in a new envelope to remove any Polish signs and only then could be delivered to Lithuania.<ref name="lengyel" /> Despite several attempts to normalize the relations, the situation of "no war, no peace", lasted until Poland demanded to re-establish diplomatic relations by issuing the [[1938 Polish ultimatum to Lithuania|ultimatum of 1938]].{{Sfn|Eidintas|Žalys|Senn|1999|p=85}} These tensions were one of the reasons that Józef Piłsudski's [[Międzymorze]] federation was never formed.<ref name="loss1991" /> The Soviets gave Vilnius to Lithuania after the [[Soviet invasion of Poland]] in September 1939.<ref name="cassell" />

== See also ==

* [[List of wars between democracies]]

==Notes==
{{Notelist}}

==References==
{{reflist|3|refs=

<ref name=bojtar>{{cite book|author=Endre Bojtár|title=Foreword to the Past: A Cultural History of the Baltic People|url=https://books.google.com/books?id=5aoId7nA4bsC&pg=PA202|access-date=14 May 2012|year=1999|publisher=Central European University Press|isbn=978-963-9116-42-9|page=202}}</ref>

<ref name=Brensztejn>{{cite book|first= Michał Eustachy |last=Brensztejn|year=1919 |title=Spisy ludności m. Wilna za okupacji niemieckiej od. 1 listopada 1915 r. |publisher=Biblioteka Delegacji Rad Polskich Litwy i Białej Rusi, [[Warsaw]]|language=pl}}</ref>

<ref name=BuchKr>{{cite journal|first=Krzysztof |last=Buchowski |author-link=Krzysztof Buchowski |url=http://www.lkma.lt/annuals/23annual_en.html#a15 |title=Polish-Lithuanian Relations in Seinai Region at the Turn of the Nineteenth and Twentieth Centuries |journal=The Chronicle of Lithuanian Catholic Academy of Sciences|issue=XXIII |volume=2 |year=2003 |archive-url = https://web.archive.org/web/20070927015825/http://www.lkma.lt/annuals/23annual_en.html#a15 |archive-date = 2007-09-27}}</ref>

<ref name=BuchSt>{{cite web | first=Stanisław | last=Buchowski | title=Powstanie Sejneńskie 23-28 sierpnia 1919 roku | publisher=Gimnazjum Nr. 1 w Sejnach | url=http://www.g1.powiat.sejny.pl/strony/buchowski.htm | access-date=2007-09-27 | language=pl | archive-url=https://web.archive.org/web/20080610050258/http://www.g1.powiat.sejny.pl/strony/buchowski.htm | archive-date=2008-06-10 | url-status=dead }}</ref>

<ref name=cassell>{{cite book| first=J. Lee |last=Ready |year=1995 |title=World War Two. Nation by Nation |location=London |publisher=Cassell |page=191 |isbn= 1-85409-290-1}}</ref>

<ref name=cepenas>{{cite book |last=Čepėnas |first=Pranas |author-link=Pranas Čepėnas |title=Naujųjų laikų Lietuvos istorija |year=1986 |publisher=Dr. Griniaus fondas |location=Chicago |page=634}}</ref>

<ref name=cepenas355>{{cite book |last= Čepėnas |first= Pranas |author-link= Pranas Čepėnas | title=Naujųjų laikų Lietuvos istorija |volume= II |year= 1986 |publisher= Dr. Griniaus fondas | location= Chicago |isbn= 5-89957-012-1 |pages= 355–359|language=lt}}</ref>

<ref name=demoskop>{{in lang|ru}} [http://demoscope.ru/weekly/ssp/rus_lan_97.php?reg=32 Demoscope].</ref>

<ref name=yearwood>{{cite book| title=Guarantee of Peace: The League of Nations in British Policy 1914–1925| url=https://books.google.com/books?id=avdCwYTjpY8C&pg=PA186 |first=Peter J. |last=Yearwood |publisher=Oxford University Press US |isbn=978-0-19-922673-3 |page=188| date=2009-02-15}}</ref>

<ref name=loss1995>{{cite book| author-link=Piotr Łossowski |first=Piotr |last=Łossowski |title=Konflikt polsko-litewski 1918–1920 |location=Warsaw |publisher=Książka i Wiedza |year=1995 |isbn=83-05-12769-9 |page=11 |language=pl}}</ref>

<ref name=los166-175>{{cite book| author-link=Piotr Łossowski |first=Piotr |last=Łossowski |title=Konflikt polsko-litewski 1918–1920 |location=Warsaw |publisher=Książka i Wiedza |year=1995 |isbn=83-05-12769-9 |pages=166–175|language=pl}}</ref>

<ref name=loss1991>{{cite book |last=Łossowski |first=Piotr |author-link=Piotr Łossowski |title=Polska-Litwa: Ostatnie sto lat |year=1991 |publisher=Wydawnictwo Oskar |location=Warsaw |page=110|language=pl}}</ref>

<ref name=manczuk>{{cite journal | first=Tadeusz | last=Mańczuk | year=2003 | title=Z Orłem przeciw Pogoni. Powstanie sejneńskie 1919 | journal=[[Mówią Wieki]] | volume=12 | issue=258 | pages=32–37 | url=http://mowiawieki.pl/artykul.html?id_artykul=860 | language=pl | url-status=dead | archive-url=https://web.archive.org/web/20071223034311/http://www.mowiawieki.pl/artykul.html?id_artykul=860 | archive-date=2007-12-23 }}</ref>

<ref name=msn>{{cite web |url=http://encarta.msn.com/sidebar_461500494/1938_lithuania.html |title=1938: Lithuania |publisher=MSN Encarta |work=Collier's Year Book |access-date=2008-03-14 |url-status=dead |archive-url=https://web.archive.org/web/20090831224924/http://encarta.msn.com/sidebar_461500494/1938_Lithuania.html |archive-date=2009-08-31 }}</ref>

<ref name=lengyel>{{cite journal | journal=The New York Times |first=Emil |last=Lengyel |date=1939-03-20 |title=Poland and Lithuania in a Long Feud |page=63}}</ref>

<ref name=drilinga>{{cite book| title=Lietuvos Respublikos prezidentai |editor-last=Drilinga |editor-first=Antanas |publisher=Valstybės leidybos centras |location=Vilnius |year=1995 |page=54 | isbn=9986-09-055-5|language=lt}}</ref>

<ref name=racis>{{cite encyclopedia| title=Reguliariosios pajėgos |volume=I |encyclopedia=Lietuva | editor-first=Antanas |editor-last=Račis |year=2008 |publisher=[[Science and Encyclopaedia Publishing Institute]] |isbn=978-5-420-01639-8 |pages=454–456 |language=lt}}</ref>

<ref name=Seibt>{{cite book |first=Ferdinand |last=Seibt | title =Handbuch der europäischen Geschichte | pages =1072–1073 |publisher =Union Verlag | location =Friedrichstadt | isbn =3-12-907540-2 | url =https://books.google.com/books?id=LekfAAAAMAAJ&q=Sejny+1920 |year=1992|language=de}}</ref>

<ref name=Senn>[[Alfred Erich Senn]], ''The Formation of the Lithuanian Foreign Office, 1918–1921'', Slavic Review, Vol. 21, No.  3. (Sep., 1962), pp.  500–507.: ''"A Bolshevik victory over the Poles would have certainly meant a move by the Lithuanian communists, backed by the Red Army, to overthrow the Lithuanian nationalist government... Kaunas, in effect, paid for its independence with the loss of Vilna."''<br/>Alfred Erich Senn, ''Lietuvos valstybes...'' p.  163: ''"If the Poles didn't stop the Soviet attack, Lithuania would fell to the Soviets... Polish victory costs the Lithuanians the city of Wilno, but saved Lithuania itself."''<br/>[[Antanas Ruksa]], ''Kovos del Lietuvos nepriklausomybes'', t.3, p. 417: ''"In summer 1920 Russia was working on a communist revolution in Lithuania... From this disaster Lithuania was saved by the [[miracle at Vistula]]."''<br/>Jonas Rudokas, [http://www.pogon.lt/_NCZ_ARCHYVAS/519/na_lamach.html Józef Piłsudski – wróg niepodległości Litwy czy jej wybawca?] {{Webarchive|url=https://web.archive.org/web/20161011114938/http://www.pogon.lt/_NCZ_ARCHYVAS/519/na_lamach.html |date=2016-10-11 }} (Polish translation of a Lithuanian article) "Veidas", 25 08 2005: ''[Piłsudski] "defended both Poland and Lithuanian from Soviet domination"''</ref>

<ref name=eudin>{{cite book| title=Soviet Russia and the West, 1920–1927: A Documentary Survey |first=Xenia Joukoff |last=Eudin |author2=Harold Henry Fisher |url=https://archive.org/details/sovietrussiawest00eudi | url-access=registration |publisher=Stanford University Press |isbn=0-8047-0478-3 |pages=[https://archive.org/details/sovietrussiawest00eudi/page/10 10]–11| year=1957}}</ref>

<ref name=suziedelis>{{cite book |last1=Sužiedėlis |first1=Saulius |title=Historical Dictionary of Lithuania |date=2011 |publisher=Scarecrow Press |isbn=978-0-8108-4914-3|url=https://books.google.com/books?id=VkGB1CSfIlEC&pg=PA286| edition=2nd|page=286 }}</ref>

<ref name=tarja>{{cite book|title=Transformation in Russia and International Law |url=https://books.google.com/books?id=_Y1ITouKQooC&pg=PA52 |first=Tarja |last=Langstrom |publisher=Martinus Nijhoff Publishers  |isbn=90-04-13754-8 |page=52|date=January 2003}}</ref>

<ref name=untc>{{cite web | publisher=United Nations Treaty Collection | url=http://untreaty.un.org/unts/60001_120000/20/14/00038658.pdf | title=Lithuania and Poland. Agreement with regard to the establishment of a provisional "Modus Vivendi", signed at Suwalki, October 7, 1920 | access-date=2009-08-01 | url-status=dead | archive-url=https://web.archive.org/web/20110723021945/http://untreaty.un.org/unts/60001_120000/20/14/00038658.pdf | archive-date=July 23, 2011}}</ref>

<ref name=davies>{{cite book | author-link= Norman Davies |last= Davies |first = Norman |title= White Eagle, Red Star: the Polish-Soviet War, 1919–20 |publisher= Pimlico |year= 2003 |isbn = 0-7126-0694-7 |orig-year= 1972 |page=50}}</ref>

<ref name=wrzosek>{{cite journal |first=Mieczysław |last=Wrzosek |author2=Grzegorz Łukomski |author3=Bogusław Polak  |title =Wojna polsko-bolszewicka, 1919-1920: działania bojowe - kalendarium |journal=Bitwy Września 1939 R.: Materiały ... Seminarium Historyków Wojny Obronnej 1939 |pages =136–142 | publisher =Wyższa Szkoła Inżynierska | location =Koszalin | url =https://books.google.com/books?id=GJUdAAAAMAAJ&q=Sejny+1920 |year=1990|language=pl|issn=0239-7129}}</ref>

<ref name=salzmann>{{cite book |first=Stephanie C. |last= Salzmann |title= Great Britain, Germany and the Soviet Union: Rapallo and After, 1922-1934  | publisher= Boydell Press |year=2013 | isbn= 9781-843-83840-1|page= 93}}</ref>
}}

== Bibliography ==
{{refbegin}}
*{{cite encyclopedia |encyclopedia=Lietuvių enciklopedija |title=Lietuvos kariuomenė (1918–1944) |first=Kazys |last=Ališauskas |location=Boston, Massachusetts |publisher=Lietuvių enciklopedijos leidykla |year=1968 |volume=XV |oclc=14547758 |language=lt}}
* {{Cite book |last=Balkelis |first=Tomas |url=https://books.google.com/books?id=LZRODwAAQBAJ |title=War, revolution, and nation-making in Lithuania, 1914-1923 |year=2018 |isbn=9780199668021 |publisher=Oxford University Press |editor-last=Gerwarth |editor-first=Robert |pages= |oclc=1039838658}}
* {{cite book |first=Jerzy |last=Borzęcki |title=The Soviet–Polish Peace of 1921 and the Creation of Interwar Europe  |url=https://books.google.com/books?id=wjsk1sdZzdIC&pg=PA140 |publisher=Yale University Press |isbn=978-0-300-12121-6 |date=2008}}
*{{cite book |last1=Eidintas |first1=Alfonsas |first2=Vytautas |last2=Žalys |first3=Alfred Erich |last3=Senn |editor-first=Edvardas |editor-last=Tuskenis |title=Lithuania in European Politics: The Years of the First Republic, 1918-1940 |edition=Paperback |year=1999 |publisher=St. Martin's Press |location=New York |isbn=0-312-22458-3}}
* {{cite book |last=Gerutis |first=Albertas |editor-first=Albertas |editor-last=Gerutis |others=translated by Algirdas Budreckis |title=Lithuania: 700 Years |year=1984 |edition=6th |publisher=Manyland Books |location=New York |isbn=0-87141-028-1 |chapter=Independent Lithuania|lccn=75-80057 }}
* {{cite book |first=Thomas A. |last=Lane |url=https://books.google.com/books?id=fecMC0LXU-sC&pg=PA7 |title=Lithuania: Stepping Westward  |publisher=Routledge |isbn=0-415-26731-5 |year=2001}}
*{{cite book |last=Lesčius |first=Vytautas |title=Lietuvos kariuomenė nepriklausomybės kovose 1918–1920 |publisher=[[Vilnius University]], [[Generolo Jono Žemaičio Lietuvos karo akademija]] |year=2004 |location=Vilnius |url=https://biblioteka.lka.lt/data/Leidiniai/Moksliniai/2004-LT%20kariuomene%20nepriklausomybes%20kovose%201918-1920.pdf |isbn=9955-423-23-4 |language=lt}}
*{{cite book |first=Piotr |last=Łossowski |title=Stosunki polsko-litewskie w latach 1918–1920 |year=1966 |publisher=Książka i Wiedza |location=Warsaw |oclc=9200888 |language=pl}}
*{{cite book |first=Piotr |last=Łossowski |title=Konflikt polsko-litewski 1918 - 1920 |year=1996 |location=Warsaw |language=pl}}
*{{cite book |title=The Baltic States: The Years of Independence |first=Georg von |last=Rauch |year=1970 |publisher=University of California Press |isbn=0-520-02600-4}}
* {{Cite book |last=Rudling |first=Per Anders |url=http://worldcat.org/oclc/909236805 |title=The rise and fall of Belarusian nationalism, 1906-1931 |isbn=978-0-8229-6308-0 |editor-last=Harris |editor-first=Jonathan |series=Pitt Series in Russian and East European Studies |date=22 December 2014 |oclc=909236805}}
* {{cite book |first=Alfred Erich |last=Senn |title=The Great Powers: Lithuania and the Vilna Question, 1920–1928 |url=https://books.google.com/books?id=180UAAAAIAAJ&pg=PA45 |publisher=Brill Archive |year=1966 |series=Studies in East European history |lccn=67086623 }}
*{{cite book |first=Alfred Erich |last=Senn |title=The Emergence of Modern Lithuania |publisher=Greenwood Press |orig-year=1959 |year=1975 |isbn=0-8371-7780-4}}
* {{Cite book |last=Srebrakowski |first=Aleksander |url=http://hist.uni.wroc.pl/pdf/srebrakowski/srebrakowski7.pdf |title=Konflik polsko-litewski na tle wydarzeń roku 1920 |year=2001 |language=pl |archive-url=https://web.archive.org/web/20190303223250/http://hist.uni.wroc.pl/pdf/srebrakowski/srebrakowski7.pdf |archive-date=3 March 2019 |url-status=dead}}
* {{cite book |author-link=Timothy Snyder |first=Timothy |last=Snyder |title=The Reconstruction of Nations: Poland, Ukraine, Lithuania, Belarus, 1569–1999 |publisher=Yale University Press |year=2003 |isbn=0-300-10586-X |url=https://books.google.com/books?id=xSpEynLxJ1MC&pg=PA64}}
*{{cite book |title=Lietuvos ir Lenkijos santykiai Tautų Sąjungoje |last=Vilkelis |first=Gintaras |publisher=Versus aureus |year=2006 |isbn=9955-601-92-2 |language=lt}}
* {{cite book | first =Lech |last=Wyszczelski | title =Wilno 1919-1920 | year =2008 | publisher =Bellona | location =Warsaw | isbn=978-83-11-11249-0 |language=pl}}
* {{Cite journal |last=Budreckis |first=Algirdas |date=November 1963 |title=Lietuvos kariuomenės kūrimasis |url=http://www.partizanai.org/failai/pdf/01Karys/Karys-1963-9.pdf |journal=[[Karys]] |language=lt |volume=9 |issue=1396}}
{{refend}}
{{World War I}}
{{Lithuanian wars and conflicts}}
{{Lithuania topics}}
{{Polish wars and conflicts}}
{{Authority control}}

{{DEFAULTSORT:Polish-Lithuanian War}}
[[Category:Polish–Lithuanian War| ]]
[[Category:1919 in Poland]]
[[Category:1919 in Lithuania]]
[[Category:1920 in Poland]]
[[Category:1920 in Lithuania]]
[[Category:Polish–Soviet War]]
[[Category:Lithuania–Poland military relations]]
[[Category:Poland in the Russian Civil War]]
[[Category:Lithuania–Second Polish Republic relations]]
[[Category:Lithuania in the Russian Civil War]]