Frontinus (Sextus Julius Frontinus) (frŏntī´nəs), fl. AD 74, Roman administrator and writer. As governor of Britain from AD 74 or AD 75 to AD 78, he reduced the Silures, a rebellious tribe in SE Wales, and pacified Britain within its borders; it was this work, successfully done, that probably rendered possible the achievements of Frontinus' successor, Agricola. From his experience as curator aquarum, or water commissioner, he wrote De aquis urbis Romae, which treats exhaustively of the water supply of Rome, with complete descriptions and history of the aqueducts. He also wrote the Strategematica, which is important as a guide to Roman military tactics and strategy.