in Roman antiquity, a body of foot which consisted of ten cohorts. The word comes from the Latin legere, to choose; because, when the legions were raised, they made choice of such of their youth as were most proper to bear arms.

The exact number contained in a legion was fixed by Romulus at 5000; though Plutarch assures us, that after the reception of the Sabines into Rome, he increased it to 6000. The common number afterwards in the first times of the free state was 4000; but in the war with Hannibal it rose to 5000; and after that it is probable that it sunk again to 4000, or 4200, which was the number in the time of Polybius.

They borrowed their names from the order in which they were raised, as prima, secunda, tertia; but because it usually happened that there were several prime, secunda, &c. in several places, they, on that account, took a sort of surname besides, either from the emperors who first constituted them, as Augusta, Claudiana, Galbiana; or from the provinces which had been conquered chiefly by their valour, as Parthica, Scythica, Gallica, &c. or from the names of the particular deities for whom their commanders had an especial honour, as Minervia and Apollinaris; or from the region where they had their quarters, as Cretenis, Cyrenaica, Britannica, &c. or sometimes upon account of lesser accidents, as Ajutrix, Martia, Fulminatrix, Rapax, &c.