An inscription upon the face of the _specus_ itself in the wall of the city over the archway, records that Claudius the son of Drusus, caused to be brought into the city the water of the Claudian conduit, from the springs called Cæruleus and Curtius, from 45 miles distance; also the water of the Anio Novus, from 62 miles, at his own expense[141]. These dates here given correspond with the year 798 of Rome, or A.D. 45. Great repairs were made by Vespasian and Titus to the Claudian aqueduct. The distance from which the Anio Novus is brought, according to this inscription[142], is 62 miles, which agrees with Frontinus[143]. The architect of the Claudian is believed to have been Claudius Annius Bassus, mentioned by Tacitus as chief engineer at Carthage under Marcus Silanus, the father-in-law of Caligula. The remains of the tomb of Bassus may be seen near Vicovaro. The tomb of another architect and his family, on the side of the _agger_ upon which the arcade of Nero stands, near the Porta Maggiore, was excavated in 1865. From its situation immediately under the _Neronian Arcade_ against the bank on which it stands, there seems no doubt that this Tiberius Claudius Vitalis, whose name is inserted on the front of the tomb, was the architect of the arcade; and it does infinite credit to him, for it is one of the finest pieces of brickwork in the world. This arcade, commonly called the Arches of Nero, carried the _specus_ of the Claudia[144] and Anio Novus combined. It first crosses the foss on a double arcade, one upon the other, to give more height across this wide and deep inner trench; it is then carried on a high bank, and therefore on a single arcade only to the Lateran, and on another bank across the foss between the Lateran and the City to the Cœlian, and along the north side of S. Stefano Rotondo to the reservoir and _piscina_ over the arch of Dolabella. This arch was the principal entrance to that part of the Cœlian in which the _Claudium_, or courts and temple of Claudius, were situated. There are magnificent ruins of a large _castellum aquæ_ over this arch, faced with the beautiful brickwork of Nero; in part of this the small church of S. Thomas in Formis has been made.