Praetorians, Or Praetorian Cohorts, a Eoman body guard, named in imitation of the cohort said to have been formed by Scipio Africanus out of his bravest troops. Their number increased during the civil wars, and by Augustus they were established as a separate force, of nine cohorts, each containing 1,000 men. Three cohorts he stationed in Eome, retaining the others in the adjacent towns. But Tiberius assembled them all at Rome in a permanent fortified camp, and Vitellius increased the number of cohorts to 16. They received double pay. Their term of service was at first 12 years, but at a later period 16, and at the end of the term each soldier received 20,000 sesterces. All the prsstorians were entitled to carry the same insignia of rank with the centurions. They became very influential in the imperial succession, and received large donations from each emperor at his accession; and in A. D. 193, having assassinated Pertinax, who attempted reforms, they even put the empire up for sale. Upon the accession of Sep-timius Severus in the same year, they were disbanded and banished from the city. Severus afterward restored them with a new organization, increasing their number fourfold, and recruiting them, not as formerly from Italy only, but from the bravest soldiers of the frontier legions.

Upon the removal of the seat of the emperor from Rome they ceased to guard his person. They were increased by Maxentius, but were defeated with him in 312 by Oonstantine, who entirely suppressed them.