When the civil war was ended by the triumph of the strong, sensible, common-place emperor Vespasian, a new impulse was given to Roman conquest in Britain. Petillius Cerialis, a near relative of the new emperor, a capable if somewhat rash soldier, the same who, at the head of the Ninth legion, had vainly sought to stem the torrent of Boadicea’s rebellion, held office for four years (A.D. 71–75), during which time he humbled and perhaps subdued the Brigantes, who ever since Cartimandua’s marital troubles had been more or less at enmity with the empire. This conquest, if really made at this time, involved the addition of Yorkshire to the empire, perhaps the foundation of Eburacum (York), once the capital of Roman Britain. Julius Frontinus (A.D. 75–78) followed Cerialis, and completed the long-delayed subjugation of the Silures in South Wales, who at this time, twenty-four years after Caratacus had been led in triumph through the streets of Rome, were still unreconciled to the Roman dominion. An interesting point in connexion with the name of Julius Frontinus is the fact that nearly twenty years after his return from Britain (A.D. 97) he was appointed by the Emperor Nerva _Curator Aquarum_, and in that capacity, though he was already advanced in years, carried great reforms and corrected many abuses which had grown up in connexion with the water-supply of the Eternal City. His treatise on the subject is still the source from which we derive almost all our information concerning the splendid aqueducts of Rome.