Cohort, in Roman antiquity, a division of an army, comprising three maniples or six centuries, and being the tenth part of a legion. It contained from 400 to 600 men, according to the number in the legion. There was one cohort (cohors milliaria) which had precedence over the others, and consisted of 1,000 select men. It marched in the van, carried the eagle, and was commanded by a tribune of approved valor. Marius, who during the wars with the Cimbri introduced tactical reforms into the Roman army, was the first who organized the legion into ten cohorts. The praetorian cohorts were the special guards successively of the generals, triumvirs, and emperors, and exerted great influence during the decline of the empire. Augustus organized nine of them, which he retained as a standing army in the vicinity of Rome, under the command of two prefects. Tiberius placed them under a single prefect, and gave them a fortified camp within the walls. (See PeAEtorians.) - When Napoleon organized the legion of honor, he divided it into 16 cohorts.