When it became clear to him that Aetius, the commander-in-chief of the Roman army, had to focus all his attention to preserve Gaul, first by defeating the Burgundy uprising in 436 and then holding his hands full at the Gothic War, Geiseric decided it was time to realize his plans.
[1] Geiseric had defeated the Roman army in Africa twice, once in the battle of Calama against Bonifatius and twice when it was reinforced by troops from the east, so the trust must have been great with him.
In Italy, this news caused the necessary fear, as the cities of Rome and Naples were brought into a state of defense [3] and Sigiswult, master of soldiers, took steps to guard the shores.
[4] Geiseric may have been aware that preparations had been made against him in Italy, because after the conquest of Carthage he concentrated his attack on Sicily, where he besieged Panormus.
[7] The following year Theodosius had prepared a large naval squadron sailing westward, with the aim of freeing Carthage from the Vandals.
Prosper writes that the imperial fleet was commanded by three generals, Areobindus, Ansila and Germanus [8] This expedition arrived in Sicily in 441 after which the island was purged of Vandals.
This diplomatic consultation took a lot of time, and in the meantime an invasion of the Huns forced Theodosius to bring back his fleet.
[9] Aetius had every interest in the West having good relations with Geiseric, in order to prevent him from having a pretext for attacks on Sicily, or Sardinia, or Italy itself.
It is suspected that he managed to persuade Valentinianus to agree to the engagement between his eldest daughter Eudocia, and the son of Geyseric Hunerik.
The West lost its grain deliveries from Africa, but even more importantly also the tax revenues, with which it, among other things, financed its expensive army of military forces.
After the conquest of Carthage, most landowners who were part of the Roman senatorial class were forced to leave the coasts of Africa, some sailed to Italy, others sought refuge in the east.