XII.--Vercingetorix, when he ascertained the arrival of Caesar, desisted from the siege [of Gergovia], and marched to meet Caesar. The latter had commenced to besiege Noviodunum; and when ambassadors came from this town to beg that he would pardon them and spare their lives, in order that he might execute the rest of his designs with the rapidity by which he had accomplished most of them, he orders their arms to be collected, their horses to be brought forth, and hostages to be given. A part of the hostages being now delivered up, when the rest of the terms were being performed, a few centurions and soldiers being sent into the town to collect the arms and horses, the enemy's cavalry, which had outstripped the main body of Vercingetorix's army, was seen at a distance; as soon as the townsmen beheld them, and entertained hopes of assistance, raising a shout, they began to take up arms, shut the gates, and line the walls. When the centurions in the town understood from the signal-making of the Gauls that they were forming some new design, they drew their swords and seized the gates, and recovered all their men safe. XIII.--Caesar orders the horse to be drawn out of the camp, and commences a cavalry action. His men being now distressed, Caesar sends to their aid about four hundred German horse, which he had determined, at the beginning, to keep with himself. The Gauls could not withstand their attack, but were put to flight, and retreated to their main body, after losing a great number of men. When they were routed, the townsmen, again intimidated, arrested those persons by whose exertions they thought that the mob had been roused, and brought them to Caesar, and surrendered themselves to him. When these affairs were accomplished, Caesar marched to the Avaricum, which was the largest and best fortified town in the territories of the Bituriges, and situated in a most fertile tract of country; because he confidently expected that on taking that town, he would reduce beneath his dominion the state of the Bituriges.