The effective power of Avitus depends on…

Emperor Marcian sends an embassy to Carthage in March 456 to end the Vandal raids in the Mediterranean from their strongholds in North Africa; he also quells disturbances on the Armenian frontier.

Emperor Marcian refuses to become entangled in war with the Vandals in Africa, but minor troubles with nomadic peoples in Syria and along the frontier of southern Egypt have occurred during his reign, including a revolt by the Samaritans.

The Vandals had next plundered the coasts of Dalmatia and …

…Greece.

There is no general cessation of trade, but this activity accelerates the breakup of the economic unity of the western Mediterranean, already threatened by the creation of the other barbarian kingdoms.

Treaties under Marcian and a treaty of 442 between emperor Valentinian III and the Vandal king Gaiseric had failed to reduce Vandal incursions and raids along the Italian coast.

Avitus' own efforts have secured a temporary winter truce with them; but in March 456, Vandals destroy Capua.

Avitus sends Ricimer to defend Sicily, and the Romans defeat the Vandals twice, once in a land battle near Agrigento and another in a naval battle off Corsica.

Resentment among the population of Italy against the foreigner Avitus meanwhile grows.

The Gallic-Roman Emperor has given to other members of the Gallic-Roman aristocracy many key offices of the public administration usually filled by Romans.

Furthermore the population of Rome, devastated by the sack of Rome, suffers from food shortages due to the Vandal control of the naval routes, aggravated by the requirements of the foreign troops that had arrived with Avitus.

The imperial treasury is almost empty and, after disbanding his Visigoth guard because of popular pressure, Avitus is obliged to pay their huge wages by melting down and selling the bronze of some statues.

Counting on the popular discontent, on the disbandment of the imperial guard, and on the prestige gained through their victories, Ricimer and the comes domesticorum Majorian rebel against Avitus; the Emperor is obliged to leave Rome in early autumn and to move north.

Ricimer has the Roman Senate depose Avitus and …

…on September 17, 456, orders the murder of the magister militum Remistus in the Palatium at Classe, the ancient port of Ravenna.

During the reign of Emperor Avitus, the Visigoths expand their influence into Hispania, officially acting under Roman authorization, but in reality, pursuing their own interests.

In 455 CE, Avitus dispatches an ambassador, Comes Fronto, to the Suebi, and later to Visigothic King Theodoric II, seeking formal recognition of Roman rule. However, tensions escalate when the Suebi invade the Roman province of Hispania Tarraconensis.

In response, the Visigoths launch an offensive, decisively defeating the Suebi on October 5, 456, at the Campus Paramus, twelve miles from Astorga, near the Órbigo River (Urbicus). Following their victory, the Visigoths occupy Hispania Tarraconensis, nominally as foederati of the Empire, but effectively asserting their own dominance over the region.

The Visigoths, in their campaign against the Suebi, brutally sack Braga, the Suebi capital, reducing it to ruins and burning its churches to the ground.

King Rechiar is captured and later executed, marking a devastating blow to Suebi power.

Despite this defeat, remnants of the Suebi kingdom survive under King Maldras (r. 456–460) and a series of rival claimants, as internal divisions fragment their rule.