This is not the only ingenious device in the Coliseum. The substructure piers along the arena’s long axis are cut obliquely. Why? Cozzo reasoned that on them rested, at an angle below the horizontal, hinged sections of the area flooring, on which stage sets could be placed, and the whole section of flooring raised by counterweights to the arena level, to provide appropriate backdrops or scenery for the fights. Against such backdrops, scenes from myth or history were acted out, the protagonists tortured to death before delighted spectators. We hear of 11,000 beasts, and 5,000 pairs of gladiators, fighting to the death in one session in the arena. In 1937, demolition of houses east of the Coliseum revealed the ground plan of part of the gladiators’ barracks, with armory, infirmary, baths, and, for training bouts, a miniature amphitheater, with seats for rabid fans (Fig. 9.7). To celebrate the millennium of Rome, in A.D. 248, elephants, elk, tigers, lions, leopards, hyenas, hippopotamuses, a rhinoceros, zebras, giraffes, wild asses, and wild horses (captured in Africa; see Fig. 13.5) were slaughtered in the Coliseum. This market of flesh did not cease till the sixth Christian century. * * * * * Vespasian did not live to see the Coliseum completed. It was dedicated, still unfinished, under Titus in A.D. 80. The chief surviving monument of Titus’ reign is his arch, commemorating his conquest of the Jews in A.D. 70, but, since the inscription upon it refers to him as deified, it is clear that the arch was not finished until after his death. Built of valuable Pentelic marble, it would never have been preserved if it had not been incorporated, in the Middle Ages, into a fortress of the powerful family of the Frangipani. The last vestiges of the Frangipani tower were not removed from the arch until 1821. It was then reinforced and its missing portions restored in travertine. It is chiefly famous for the relief on its inner jamb showing (Fig. 9.8) Titus’ army carrying in triumph the spoils of Jerusalem, including the table of the shewbread, the seven-branched candlestick, and the silver trumpets. In the relief opposite, Titus stands in a four-horse chariot, with the goddess Roma leading the horses, and Victory crowning him with a laurel wreath. The frieze under the cornice, not unrelated to the small inner altar frieze of the Altar of Peace, portrays a procession of priests, sacrificial animals, and troops carrying on their shoulders small platforms bearing representations of cities and places conquered by Roman arms, including a personification of the River Jordan. The motif in the highest part of the inner vault, showing Titus--who was a burly man--carried off to heaven by an eagle, is as conventional as the Ganymede in the vault of the underground basilica at the Porta Maggiore. In the years since Augustus, Roman official art had become conventional without ceasing to be historical.