fully developed.[77] Hadrian, the cultured, travelling Philhellene, encouraged a reversion to the classical traditions of Greek art. The art of his period was profoundly influenced by the type of Antinous, a beautiful youth beloved by the emperor, whose romantic death by drowning in the Nile made a powerful impression upon the whole Roman world, because he was believed to have sacrificed his life for his emperor’s in obedience to an oracle. This type is preserved for us in many forms, but most notably in the colossal Mondragore bust in the Louvre[78] and the bas-relief in the Villa Albani.[79] His features were utilised to represent all the young male gods on Olympus. In their tragic beauty we see a mirror of Greece tinged by the Orient, as if Dionysus had wedded Isis and this were the offspring. The Antonine period, as exhibited on the panels in the Palazzo dei Conservatori, is gifted with immense technical fluency and, as Mrs. Strong remarks, a new spiritual seriousness. As compositions they are superb, but the weakness of expression in the face of Marcus Aurelius himself quite spoils their effect for some spectators.[80] Architecture was still mainly designed in the three Greek modes variously combined, in spite of the fact that Rome had progressed far beyond Greek limits in constructional ability. Roman builders could manage a roof-span far in excess of the Greeks. The Roman arch gave a strength in concrete vaulting which expensive marble was unable to attain. Roman brickwork denuded of the marble incrustations which generally covered it of old is probably more impressive in its ruins than it was when it was draped with Hellenism, and, to me at least, remains like the aqueduct at Pont du Gard[81] and the Bridge of Alcantara[82] seem truer witnesses of the grandeur of Rome than all the marbles in all the museums. The celebrated Castle of St. Angelo, which still keeps watch and ward over the Tiber, is nothing but the core of Hadrian’s tomb--the _Moles Hadriani_--once clad in a vestment of Greek marbles and covered with Greek ornament.[83] The Pantheon, in spite of the inscription which ascribes it to Agrippa, is proved by the marks on its bricks to be a restoration of Hadrian’s time. It is indeed a superb example of vaulting and a miracle of construction. The plan is that of a dome so constructed that if the sphere were complete it would rest upon the earth. The magnificent interior has lost little of its ancient splendour.[84]