LEGION (Lat. legio), in early Rome, the levy of citizens marching out en masse to war, like the citizen-army of any other primitive state. As Rome came to need more than one army at once and warfare grew more complex, legio came to denote a unit of 4000-6000 heavy infantry (including, however, at first some light infantry and at various times a handful of cavalry) who were by political status Roman citizens and were distinct from the " allies," auxilia, and other troops of the second class. The legionaries were regarded as the best and most characteristic Roman soldiers, the most trustworthy and truly Roman; they enjoyed better pay and conditions of service than the " auxiliaries." In A.D. 14 (death of Augustus) there were 25 such legions: later, the number was slightly increased; finally about A.D. 290 Diocletian reduced the size and greatly increased the number of the legions. Throughout, the dominant features of the legions were heavy infantry and Roman citizenship. They lost their importance when the Barbarian invasions altered the character of ancient warfare and made cavalry a more important arm than infantry, in the late 3rd and 4th centuries A.D. In the middle ages the word " legion " seems not to have been used as a technical term. In modern times it has been employed for organizations of an unusual or exceptional character, such as a corps of foreign volunteers or mercenaries. See further ROMAN ARMY. (F. J. H.)
The term legion has been used to designate regiments or corps of all arms in modern times, perhaps the earliest example of this being the Provincial Legions formed in France by Francis I. (see INFANTRY). Napoleon, in accordance with this precedent, employed the word to designate the second-line formations which he maintained in France and which supplied the Grande Armee with drafts. The term " Foreign Legion " is often used for irregular volunteer corps of foreign sympathizers raised by states at war, often by smaller states fighting for independence. Unlike most foreign legions the " British Legion " which, raised in Great Britain and commanded by Sir de Lacy Evans (q.v.), fought in the Carlist wars, was a regularly enlisted and paid force. The term " foreign legion " is colloquially but incorrectly applied to-day to the Regiments etrangers in the French service, which are composed of adventurous spirits of all nationalities and have been employed in many arduous colonial campaigns.
The most famous of the corps that have borne the name of legion in modern times was the King's German Legion (see Beamish's history of the corps). The electorate of Hanover being in 1805 threatened by the French, and no effective resistance being considered possible, the British government wished to take the greater part of the Hanoverian army into its service. But the acceptance by the Hanoverian government of this offer was delayed until too late, and it was only after the French had entered the country and the army as a unit had been disbanded that the formation of the " King's German Regiment," as it was at first called, was begun in England. This enlisted not only ex-Hanoverian soldiers, but other Germans as well, as individuals. Lieut.-Colonel von der Decken and Major Colin Halkett were the officers entrusted with the formation of the new corps, which in January 1805 had become a corps of all arms with the title of King s German Legion. It then consisted of a dragoon and a hussar regiment, five batteries, two light and four line battalions and an engineer section, all these being afterwards increased. Its services included the abortive German expedition of November 1805, the expedition to Copenhagen in 1807, the minor sieges and combats in Sicily 1808-14, the Walcheren expedition of 1809, the expedition to Sweden under Sir John Moore in 1808, and the campaign of 1813 in north Germany. But its title to fame is its part in the Peninsular War, in which from first to last it was an acknowledged corps d'elite its cavalry especially, whose services both on reconnaissance and in battle were of the highest value. The exploit of the two dragoon regiments of the Legion at Garcia Hernandez after the battle of Salamanca, where they charged and broke up two French infantry squares and captured some 1400 prisoners, is one of the most notable incidents in the history of the cavalry arm (see Sir E. Wood's Achievements of Cavalry). A general officer of the Legion, Charles Alten (q.v.), commanded the British Light Division in the latter part of the war. It should be said that the Legion was rarely engaged as a unit. It was considered rather as a small army of the British type, most of which served abroad by regiments and battalions while a small portion and depot units were at home, the total numbers under arms being about 25,000. In 1815 the period of service of the corps had almost expired when Napoleon returned from Elba, but its members voluntarily offered to prolong their service. It lost heavily at Waterloo, in which Baring's battalion of the light infantry distinguished itself by its gallant defence of La Haye Sainte. The strength of the Legion at the time of its disbandment was noo officers and 23,500 men. A short-lived " King's German Legion " was raised by the British government for service in the Crimean War. Certain Hanoverian regiments of the German army to-day represent the units of the Legion and carry Peninsular battlehonours on their standards and colours.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)