praefectus classis
PRAEFECTUS CLASSISThis title was frequently given in the times of the Republic to the commander of a fleet (Liv. 26.48, 7, 36.42-Z2, 1, as contrasted with praefecti navium, the commanders of the several ships); but Augustus appointed two permanent officers with this title, one of whom was stationed at Ravenna on the Adriatic and the other at Misenum on the Tuscan sea, each having the command of a fleet. (Suet. Aug. 49; Veget. 4.32; Tac. Ann. 4.5, Hist. 3.12.) These were also of equestrian rank, in some cases even freedmen (Tac. Ann. 14.3; Hist. 2.100).
[W.S] [A.S.W]The commander of a Roman fleet. This title was frequently given under the Republic to the commander of a fleet; but Augustus appointed two permanent officers with this title, one of whom was stationed at Ravenna on the Adriatic, and the other at Misenum on the Tuscan Sea, each having the command of a fleet (Suet. Aug. 49).