We know from Tacitus that Nero, in his search for scapegoats on whom to shift the blame for Rome’s great fire of A.D. 64, martyred Christians in an amphitheater on the Vatican Hill, and tradition has it that in this amphitheater St. Peter, too, suffered martyrdom. It was to test the validity of this tradition that Pius XII ordered the cemetery under St. Peter’s excavated. What was found was a series of twenty-one mausolea and one open area (P in the plan, Fig. 13.7), all facing southward onto a Roman street. The mausolea are plain brick on the outside, highly baroque within, enriched with mosaics, wall-paintings, and stucco-work. There are both cremation and inhumation burials, but when the mausolea were filled in inhumation was beginning to predominate. Of the mausolea only M is entirely Christian in décor; others began as pagan, later admitting Christian burials, or adapt pagan motifs to Christian symbolism. M contains the earliest known Christian mosaics, which Ward Perkins and Miss Toynbee call a microcosm of the dramatic history of Christianity’s peaceful penetration of the pagan Roman Empire. They are dated by technique and motifs to the middle of the third century A.D. The subjects are Jonah and the whale, the Fisher of Men, the Good Shepherd, and, in the vault, Christ figured as the sun. The wall paintings of the cemetery are mostly pagan, the contractors’ stock-in-trade, depicting in myth or in symbol the soul’s victory over death. The great artistic interest of the mausolea is in the stucco-work, both in relief and in the round, superior in quality to that of the subterranean basilica at the Porta Maggiore. Some of it is of unparalleled scale and complexity, excellently preserved (Fig. 13.8), and now protected from dampness by large, constantly burning electric heaters. Of stone sculpture in the round there is very little; it was probably removed by Constantine’s workmen. But there are many marble sarcophagi with pagan and Christian motifs, testifying to the artistic revival enjoyed by the Roman world with the peace of the Church in A.D. 312. They show how the stonemasons carved them as blanks, filling in details like inscriptions and portrait busts to the customer’s order. There is a pathetic one of a baby, who died, the inscription tells us, when he was six months old. There are reliefs of Biblical scenes: the children in the fiery furnace, Joseph and his brethren, the three Magi, and what may be the earliest Christian cross, dated about A.D. 340; (an alleged cross at Herculaneum is more probably the scar of a ripped-away wall bracket). [Illustration: FIG. 13.7 Vatican City, excavations under St. Peter’s, plan of west end. (J. Toynbee and J. Ward Perkins, The Shrine of St. Peter, p. 136)] [Illustration: FIG. 13.8 Vatican City, excavations under St. Peter’s, Mausoleum F, stuccoes. (Reverenda Fabbrica di San Pietro)]