Yugoslavism
Yugoslavism refers to nationalism or patriotism centred upon the Yugoslavs - an identity referring to a united singular South Slav people and the South Slav populated territories of southeastern Europe. Yugoslavism has historically advocated the union of all South Slav populated territories now composing Bosnia and Herzegovina, Bulgaria, Croatia, Montenegro, Serbia (and the disputed region of Kosovo), Slovenia, and Macedonia. Yugoslavism was a potent political force during World War I with the assassination of Austrian Archduke Franz Ferdinand by the Yugoslavist militant Gavrilo Princip and the subsequent invasion of Serbia by Austria-Hungary, which sought to rally the South Slav peoples against Austro-Hungarian imperial domination and in support of an independent Yugoslavia that was achieved in 1918.
Background
There were sectional South Slavic ethnic nationalists who endorsed Yugoslavism as a means to achieve their ethnicity's unification. After 1878, Serbian nationalists merged their goals with those of Yugoslavists, emulating the leading role of the kingdom of Sardinia and Piedmont in the Risorgimento of Italy by claiming that Serbia sought not only to unite all Serbs in one state, but that it intended to be a South Slavic equivalent of Piedmont, uniting all South Slavs into one state to be known as Yugoslavia.Croatian nationalists became interested in Yugoslavism as a means to achieve the unification of the Croatian lands, in opposition to their division under Austria-Hungary, particularly with Yugoslavist leader Strossmayer advocating this as being achievable within a federalized Yugoslav monarchy.Slovenian nationalists such as Anton Korošec also endorsed Yugoslav unification during the First World War, seeing it as a means to free Slovenia from Austro-Hungarian rule.