Field marshal is a very senior military rank, ordinarily senior to the general officer ranks. Usually it is the highest rank in an army, and when it is, few (if any) persons are appointed to it. Considered as a five-star rank (OF-10) in modern-day armed forces in many countries.
The origin of the term dates to the early Middle Ages, originally meaning the keeper of the king's horses (from Old German Marh-scalc = "horse-servant"), from the time of the early Frankish kings.
Promotion to the rank of field marshal in many countries historically required extraordinary military achievement by a general (a wartime victory). However, the rank has also been used as a divisional command rank and also as a brigade command rank. Examples of the different uses of the rank include Austria-Hungary, Prussia and Germany for an extraordinary achievement; Spain and Mexico for a divisional command (Spanish: mariscal de campo); and France, Portugal and Brazil for a brigade command (French: maréchal de camp, Portuguese: marechal de campo).
Chom Phon (Thai:จอมพล) or Field Marshal of Thailand is a military rank of Thailand in the Royal Thai Army, considered the equivalent to a Field Marshal or General of the Army (although the former is more widely used). Today it is ceremonially held by members of the Thai Royal family and exists only on paper in the actual Thai military. The Royal Thai Navy equivalent is known as Chom Phon Ruea and Chom Phon Akat for the Royal Thai Air Force.
The King of Thailand as Head of the Armed Forces is automatically made a Chom Phon upon accession, The rank was created in 1888, together with all other ranks by King Chulalongkorn, who wanted to modernize his Armed Forces through western lines. Since then all monarchs have held this title.
Apart from these many others both inside and outside the Royal Family has been awarded this rank.
Field Marshal (FM) is a five star General officer rank and the highest attainable rank in the Sri Lanka Army. Field Marshal is ranked immediately above General and is largely a ceremonial rank, having been awarded only once. It is equivalent to an Admiral of the Fleet or a Marshal of the Air Force.
Field marshals remain officers of the Sri Lankan Army for life, with a personal staff and security detail. In the order of precedence the rank holder is equivalent to a cabinet minister.
A Field Marshal's insignia consists of the National emblem over a crossed baton and saber in a lotus blossom wreath. On appointment, Field marshals are awarded a Gold-tipped baton which they may carry on formal occasions and a personal flag.
Sarath Fonseka is the first Sri Lankan Army officer to be promoted to the rank of Field Marshal on 22 March 2015. His distinguished military career spanned four decades. Fonseka rose to be the Commander of Sri Lankan Army in 2005 and under his command, Sri Lankan forces conducted victorious campaigns against the LTTE ending the Sri Lankan Civil War in 2009. He has been described as one of the best commanders in the world. The decisive result achieved by the Sri Lankan Army during this war under the extraordinary leadership of Fonseka followed by the political victimization by President Mahinda Rajapaksa, led to his successor President Maithripala Sirisena promoting him to the newly created rank of Field Marshal in March 2015.