At last Caesar, after being joined by his last reinforcements, made a lateral movement towards Thapsus. Scipio had, as we have said, strongly garrisoned this town, and thereby committed the blunder of presenting to his opponent an object of attack easy to be seized; to this first error he soon added the second still less excusable blunder of now for the rescue of Thapsus giving the battle, which Caesar had wished and Scipio had hitherto rightly refused, on ground which placed the decision in the hands of the infantry of the line. Immediately along the shore, opposite to Caesar's camp, the legions of Scipio and Juba appeared, the fore ranks ready for fighting, the hinder ranks occupied in forming an entrenched camp; at the same time the garrison of Thapsus prepared for a sally.

Caesar's camp-guard sufficed to repulse the latter. His legions, accustomed to war, already forming a correct estimate of the enemy from the want of precision in their mode of array and their ill-closed ranks, compelled - while yet the entrenching was going forward on that side, and before even the general gave the signal - a trumpeter to sound for the attack, and advanced along the whole line headed by Caesar himself, who, when he saw his men advance without waiting for his orders, galloped forward to lead them against the enemy. The right wing, in advance of the other divisions, frightened the line of elephants opposed to it - this was the last great battle in which these animals were employed - by throwing bullets and arrows, so that they wheeled round on their own ranks. The covering force was cut down, the left wing of the enemy was broken, and the whole line was overthrown.

The defeat was the more destructive, as the new camp of the beaten army was not yet ready, and the old one was at a considerable distance; both were successively captured almost without resistance. The mass of the defeated army threw away their arms and sued for quarter; but Caesar's soldiers were no longer the same who had readily refrained from battle before Ilerda and honourably spared the defenceless at Pharsalus. The habit of civil war and the rancour left behind by the mutiny asserted their power in a terrible manner on the battlefield of Thapsus. If the hydra with which they fought always put forth new energies, if the army was hurried from Italy to Spain, from Spain to Macedonia, from Macedonia to Africa, and if the repose ever more eagerly longed for never came, the soldier sought, and not wholly without cause, the reason of this state of things in the unseasonable clemency of Caesar. He had sworn to retrieve the general's neglect, and remained deaf to the entreaties of his disarmed fellow-citizens as well as to the commands of Caesar and the superior officers. The fifty thousand corpses that covered the battle-field of Thapsus, among whom were several Caesarian officers known as secret opponents of the new monarchy, and therefore cut down on this occasion by their own men, showed how the soldier procures for himself repose. The victorious army on the other hand numbered no more than fifty dead (6 April 708).

There was as little a continuance of the struggle in Africa after the battle of Thapsus, as there had been a year and a half before in the east after the defeat of Pharsalus. Cato as commandant of Utica convoked the senate, set forth how the means of defence stood, and submitted it to the decision of those assembled whether they would yield or defend themselves to the last man - only adjuring them to resolve and to act not each one for himself, but all in unison. The more courageous view found several supporters; it was proposed to manumit on behalf of the state the slaves capable of arms, which however Cato rejected as an illegal encroachment on private property, and suggested in its stead a patriotic appeal to the slave-owners. But soon this fit of resolution in an assembly consisting in great part of African merchants passed off, and they agreed to capitulate. Thereupon when Faustus Sulla, son of the regent, and Lucius Afranius arrived in Utica with a strong division of cavalry from the field of battle, Cato still made an attempt to hold the town through them; but he indignantly rejected their demand to let them first of all put to death the untrustworthy citizens of Utica en masse, and chose to let the last stronghold of the republicans fall into the hands of the monarch without resistance rather than to profane the last moments of the republic by such a massacre. After he had - partly by his authority, partly by liberal largesses - checked so far as he could the fury of the soldiery against the unfortunate Uticans; after he had with touching solicitude furnished to those who preferred not to trust themselves to Caesar's mercy the means for flight, and to those who wished to remain the opportunity of capitulating under the most tolerable conditions, so far as his ability reached; and after having thoroughly satisfied himself that he could render to no one any farther aid, he held himself released from his command, retired to his bedchamber, and plunged his sword into his breast.

Of the other fugitive leaders only a few escaped. The cavalry that fled from Thapsus encountered the bands of Sittius, and were cut down or captured by them; their leaders Afranius and Faustus were delivered up to Caesar, and, when the latter did not order their immediate execution, they were slain in a tumult by his veterans. The commander-in-chief Metellus Scipio with the fleet of the defeated party fell into the power of the cruisers of Sittius and, when they were about to lay hands on him, stabbed himself. King Juba, not unprepared for such an issue, had in that case resolved to die in a way which seemed to him befitting a king, and had caused an enormous funeral pile to be prepared in the market-place of his city Zama, which was intended to consume along with his body all his treasures and the dead bodies of the whole citizens of Zama.

But the inhabitants of the town showed no desire to let themselves be employed by way of decoration for the funeral rites of the African Sardanapalus; and they closed the gates against the king when fleeing from the battle-field he appeared, accompanied by Marcus Petreius, before their city. The king - one of those natures that become savage amidst a life of dazzling and insolent enjoyment, and prepare for themselves even out of death an intoxicating feast - resorted with his companion to one of his country houses, caused a copious banquet to be served up, and at the close of the feast challenged Petreius to fight him to death in single combat. It was the conqueror of Catilina that received his death at the hand of the king; the latter thereupon caused himself to be stabbed by one of his slaves. The few men of eminence that escaped, such as Labienus and Sextus Pompeius, followed the elder brother of the latter to Spain and sought, like Sertorius formerly, a last refuge of robbers and pirates in the waters and the mountains of that still half-independent land.

Without resistance Caesar regulated the affairs of Africa. As Curio had already proposed, the kingdom of Massinissa was broken up. The most eastern portion or region of Sitifis was united with the kingdom of Bocchus king of East Mauretania[51], and the faithful king Bogud of Tingis was rewarded with considerable gifts. Cirta (Constantine) and the surrounding district, hitherto possessed under the supremacy of Juba by the prince Massinissa and his son Arabion, were conferred on the condottiere Publius Sittius that he might settle his half-Roman bands there[52]; but at the same time this district, as well as by far the largest and most fertile portion of the late Numidian kingdom, were united as "New Africa", with the older province of Africa, and the defence of the country along the coast against the roving tribes of the desert, which the republic had entrusted to a client-king, was imposed by the new ruler on the empire itself.