In its second phase another thirty-six feet of wall was fitted on to the base provided by Aurelian’s. In some places the addition was only six feet thick, the other half of the original width being left as a passage for the circulation of materials and messages. A wall sixty feet high reduced the required number of defenders, since it had nothing to fear from an enemy equipped with scaling ladders. In this phase machines did the work of men: if there were two _ballistae_ to a tower, the expensive and impressive total of pieces of artillery would have been 762. Heightening the wall meant heightening the tower, sometimes to five stories. A start was made toward monumentalizing the gateways, but it petered out, though the effect can be admired in the Porta Asinaria near the Lateran, which was restored in 1957–58. For the workmanship of this phase is identical with and therefore of the same date as the Basilica and Circus of Maxentius (who reigned A.D. 306–312); when he was defeated by Constantine at the battle of the Milvian Bridge, and the capital moved to Constantinople, neither the money nor the motive for monumentality any longer existed. The next major alteration is dated by inscriptions to A.D. 401–403, the reign of Honorius. It was prompted by the threat that the city might be sacked by Alaric the Visigoth. It involved second-hand stone facing for the curtains of the wall, and square bases for the towers. The photograph (Fig. 12.10) shows this Honorian phase at the Porta Appia. The upper stories of the round towers belong to Maxentius’ addition, while halfway up the face of the curtain between the rectangular towers to the left of the gate can be seen the patching required to add Maxentius’ brickwork to the battlements of Aurelian’s original wall. (To distinguish the building phases of the Porta Appia, Richmond had to crawl into the base of a tower through a very small hole, while a small uninvited audience bet on his chances of sticking.) The new battlements were built in a way that shows that in this phase Rome could no longer afford artillery: archers replaced _ballistae_. By now the Empire is Christian, and crosses begin to appear on the keystones of the gate arches, as prophylaxis against the devil. Later, in what Richmond describes as “an age of vanishing standards of faith and hygiene,” an indulgence of 100 days was granted for kissing one of these crosses. They were no help: the wall was assaulted by earthquakes (A.D. 442), and by Goths (A.D. 536 and 546), and repeatedly repaired. Belisarius in 547 restored it all, with the help of palisades, in twenty days, and equipped it with spring-guns the force of whose projectiles could impale five men, and with mantraps or deadfalls, barrow-like devices which could be pushed over on assailants. But the repairs are botched work, appropriate to what Rome had become: no longer an Imperial capital, but a minor metropolis of an outlying Byzantine province. All