The voyage of the Imperial fleet was slow and tedious, and had the Vandal king been well served by his ambassadors there was ample time to have anticipated its attack. But Gelimer seems to have been quite ignorant of the projected expedition, and had actually sent off some of his best troops under the command of his brother, Tzazo, to suppress a rebellion which had broken out in Sardinia. Moreover, the estrangement between Vandals and Ostrogoths was a most fortunate event for the Imperial cause. In consequence of that estrangement Belisarius was able to land in Sicily to refresh his soldiers wearied with a long voyage, and to obtain accurate information as to the preparations, or rather no-preparations, of the enemy.
Early in September the army landed at the promontory of Caput-vada, about one hundred and thirty miles south-east of Carthage, and began their march towards the capital. They journeyed unopposed through friendly Catholic villages, and royal parks beautiful in verdure and abounding in luscious fruits, until, after eleven days, they arrived at the tenth milestone[141] from Carthage, and here came the shock of war. Gelimer had planned a combined attack on (13th Sept., 533) the Imperial army, by himself, operating on their rear, and his brother Ammatas making a vigorous sally from Carthage and attacking them in front. If the two attacks had been really simultaneous, it might have gone hardly with the Imperial army; but Ammatas came too soon to the field, was defeated and slain. Gelimer arriving later on in the day inflicted a partial defeat on the troops of Belisarius, but, coming to the spot where lay the dead body of his brother, he stayed so long to bewail and to bury him that Belisarius had time to rally his forces and to convert defeat into victory. Gelimer fled to the open country. Belisarius pressed on and without further opposition entered the gates of Carthage, where he was received by the majority of the citizens, who spoke the Latin tongue, and professed the Catholic faith, with unconcealed rejoicing. Some Roman merchants who had been confined for many weeks in the dungeon were (15th Sept., 533) liberated by their anxious gaoler. But the Imperial victory came too late for the captive Hilderic, as he had been already put to death in prison by order of his successor. There was thus neither friend nor foe left to bar Justinian's claim to rule as Augustus over Africa.