Belisarius was now master of Rome, but he knew that his hold on it was precarious. Witiges had settled matters with the Franks by paying them 130,000 gold solidi and ceding his Transalpine dominions in Provence. After marrying Mataswintha, the sister of the late king Athalaric, and the last scion of the house of the Amals, he resolved to return and deliver Rome. All north Italy had sent him its Gothic warriors, and 100,000 men marched under his banner to besiege Rome in the spring of 537. The defence of Rome is the greatest of all the titles to glory that Belisarius won. The walls of Aurelian were strong, but there were only 5000 men to defend their vast circuit, and within was an unruly mass of cowardly citizens, liable to all sorts of panic fears—mouths to be fed without hands to strike, for hardly a Roman took arms to aid the imperial troops. In the middle of March the Goths appeared before the walls, and pitched seven camps opposite the northern and eastern gates of the city. They then cut all the aqueducts which supplied Rome with water, and commenced the construction of siege-engines for a great assault. With the want of thoroughness that he always displayed, king Witiges made no adequate preparation for blockading the southern side of the city, or for stopping its communications with Ostia and Naples. All through the siege convoys of provisions and reinforcements were frequently able to creep into Rome by night, eluding the outposts which were all that Witiges placed on the side of the Tiber and the Campagna. A fortnight after arriving in front of the walls Witiges had his engines ready, and delivered his great assault on the northern and north-eastern fronts of the city. Everywhere the attack failed; the towers and rams which the Goths had drawn forward never reached the walls; the oxen which drew them were shot down before they neared the ditch. But thousands of wild warriors with scaling-ladders delivered assaults against innumerable portions of the enceinte. In most cases they failed entirely; the walls of Aurelian were too strong; but at two points, at opposite ends of the city, they nearly won success. At the Praenestine gate a battering-ram broke in the outer bulwarks, and a swarm of Goths was only held back by an inner entrenchment till the reinforcements of Belisarius arrived. But greater danger still was encountered at the Mausoleum of Hadrian (castle of St. Angelo), just beyond the Ælian Bridge. [Sidenote: Belisarius defends Rome, 536-37.] There the Goths filled the ditch, overwhelmed the defenders with arrows, and were fitting their ladders to the embrasures, when they were at last checked by a strange expedient. The walls of the mausoleum were lined with dozens of splendid statues, some of them figures of emperors, others the ancient spoils of Greece. At the supreme moment the desperate garrison flung these colossal figures on the besiegers below, and drove them off by the hail of marble fragments.