A legion was a military unit in the army of ancient Rome. It consisted of between 3000 and 6000 infantrymen, all Roman citizens who had volunteered for service as professional soldiers. Each legion also had a small number of cavalry (to act as scouts, couriers, etc.): most of the cavalry was provided by Rome’s allies, who also supplied large numbers of soldiers to serve in non-legionary infantry units. (These latter and the cavalry are typically referred to as auxilia, i.e., auxiliary troops.). Legionary soldiers were expected to serve, altogether, 25 years, after which they were able to retire on a state pension. During the period of the Roman Empire, i.e., from the end of the first century BCE to the fifth century CE, the number of legions was in the high 20s, but never exceeded 30. Each was identified by its number and a name (e.g., II Augusta, IX Hispana, XIV Gemina, etc.), and had its own standard which bore the symbol of the Roman eagle. In the earlier part of the first century CE legionary soldiers came overwhelmingly from Italy and southern France, but in later centuries with the extension of Roman citizenship they came increasingly from other parts of the Roman Empire.
The word legion is used in several other ways. It may refer to:
- any large military force or army, such as the French Foreign Legion (created in 1831 for foreign nationals who wished to serve in the French Armed Forces), including, in modern history (where the name is usually used for for organizations of foreign or expatriate soldiers)
- the King's German Legion, formed in 1803, originally from George III's subjects as Duke of Hanover and later from any Germanophone to fight Napoleon. It served with the British (and allied) army throughout the conflicts until disbanded in 1816.
- the Condor Legion was a unit of ultimately 7,000 'volunteers' from the [Nazi] German Luftwaffe (Air Force) and Wehrmacht (army) sent to fight for and help Franco's rebel forces in the Spanish Civil War (1936-1939). While gaining much battlefield experience and training, the Condor Legion developed methods of mass bombing of civilian centres such as Guernica. These led to the strategy and tactics of the Blitz on Britain and other, later, enemies of Germany.
- the Jewish Legion was formed in 1917 as an auxiliary unit of the British army to fight against the Ottoman Empire and liberate Palestine. In 1915, the Zion Mule Corps was formed and served at Gallipoli; in 1917, five battalions (38th, 39th, 40th, 41st and 42nd) of the Royal Fusiliers were enrolled from Jewish volunteers predominantly from Egypt, Russia, Canada, Britain and the USA. At the end of WWI in 1918, their members were reformed as the First Judaeans Battalion, dissolved soon afterwards; this was one nucleus of the Haganah, the Jewish military organization which led to the foundation of the State of Israel in 1948. There was a similar unit in the Second World War called the Jewish Brigade (formed 1944, disbanded 1946).
- the Arab Legion was formed after the United Kingdom assumed control of Transjordan in 1921. Initially a police force with responsibility for keeping order among the local tribes, it became the regular army of Transjordan and, after Jordan became an independent state in 1946, of the Kingdom of Jordan. Under their commander Lieutenant-General Sir John Bagot Glubb (Glubb Pasha) the Arab League saw action in the Second World War, fighting in the Mediterranean and in the Middle East, and in the Arab-Israeli War of 1948. (Do not confuse the Arab Legion and the Arab League: the latter is a league of independent Arab States formed in 1945 to foster cultural, economic, and military co-operation between them.)
- an association or organisation for retired servicemen and women, such as the British Legion, fully the Royal British Legion, (formed in 1921 to care for those who had suffered as a result of service in the First World War, either servicemen and women themselves or their dependants and now working for their successors in all British military conflicts); and the American Legion.
- The Légion d'honneur ('legion of honour') is the highest honour awarded in France, given for both military and civilian merit. It was instituted by Napoleon in 1802, and comes (|like the original legion) with different ranks.
- a very large number of individuals, as in the translation of the reply to Jesus’ question in the King James version of the Bible to the "unclean spirit" in Mark's Gospel, ch. 5: v 9: "My name is Legion: for we are many." There is an intermediate understanding, between 'a military unit' and 'a large number', possible in Matthew 26:53: "Thinkest thou that I cannot now pray to my Father, and he shall presently give me more than twelve legions of angels?"
- The word legion is more widely used as an adjective to mean ‘very many, numerous’, though usually in postposition, i.e., after the noun it qualifies, as in ‘Her admirers are legion’ or ‘The possibilities, though legion, are fraught with risks’.
The two words for a member of a legion, namely, legionary and legionnaire, are not interchangeable. A soldier in a Roman legion is a legionary, while a member of the French Foreign Legion (a fighting force), the British Legion and American Legion (support organizations for veterans), etc., is a legionnaire. (Legionary may also be used as an adjective, as in the first paragraph above.) The Legion of Mary, a Roman Catholic organization, has members.
Legionnaire’s (or Legionnaires’) disease, a sometimes fatal infection, caused by the bacterium Legionella pneumophila, and contracted through breathing contaminated water vapour from, e.g., cooling towers or showers, is so called because the first cases of the disease were found, in 1976, amongst those who had attended a convention of the American Legion at Philadelphia).
Note on pronunciation: The word legion is pronounced LEE-jern, IPA: /'liː dʒən/, though its Latin original, lĕgio, has a short ‘e’ /ɛ/. The |French Légion [d'honneur] has the 'pure' long '-e-' of IPA: /e/.