At this time the Vandals and Ostrogoths were no longer the dangerous enemies they had been in former days. Unaccustomed to the enervating southern climate and influenced by Roman civilization, they had rapidly lost their former energy and force. The Arian beliefs of these Germans caused unfriendly relations with the native Roman population. The continual uprisings of the Berber tribes also contributed much to the weakening of the Vandals. Justinian had a keen insight into existing conditions, and by skillful diplomacy he increased the internal discord among the Vandals, meanwhile feeling quite certain that the Germanic kingdoms would never unite to oppose him jointly, because the Ostrogoths were on bad terms with the Vandals, the orthodox Franks were constantly struggling with the Ostrogoths, and the Visigoths in Spain were too far distant to take a serious part in a war. All this encouraged Justinian in his hope of defeating each enemy separately.
The Vandal war lasted, with some peaceful intervals, from 533 to 548. Belisarius rapidly subjugated the entire Vandal kingdom by a number of brilliant victories so that Justinian could proclaim triumphantly: God, in his mercy, gave over to us not only Africa and all her provinces, but also returned our imperial insignia which had been taken away by the Vandals when they took Rome. Considering the war ended, the Emperor recalled Belisarius and the greater part of the army to Constantinople. Immediately the Moors (a native Berber tribe) rose in terrible rebellion, and the remaining troops were forced to engage in an overwhelming struggle. Belisarius' successor, Solomon, was utterly defeated and slain. The exhausting war lasted until the year 548, when the imperial power was definitely restored by a decisive victory on the part of John Troglita, a diplomatist as well as a talented general. The third hero of the imperial reoccupation of Africa, he secured complete tranquillity there for nearly fourteen years. His deeds were narrated by the contemporary African poet, Corippus, in his historical work Iohannis.