Note 120 — BOOK XXI.

This office had been first established by Augustus, who created two prefects of the prætorian cohorts, under whose command also all the soldiers in Italy were placed. Commodus raised the number to three, and Constantine to four, whom (when he abolished the prætorian cohort), he made, in fact, governors of provinces. There was one præfectus prætorio for Gaul, one for Italy, one for Illyricum, and one for the East.