FRONTINUS (Sextus Julius), an ancient Roman writer, was of consular dignity, and flourished under the emperors Vespasian, Titus, Domitian, Nerva, and Trajan. He commanded the Roman armies in Britain; was made city-prefect when Vespasian and Titus were consuls; and Nerva made him curator of the aqueducts, which occasioned his writing De aqueductibus urbis Romæ. He wrote four books upon the Greek and Roman art of war; a piece De re agraria, and another De limitibus. These have been often separately reprinted; but were all collected together in a neat edition at Amsterdam in 1661, with notes by Robertus Keuchenius. He died under Trajan.