quality:correction, information:extraction
433–454: Ascendancy of Aetius, loss of Carthage

Aetius campaigned vigorously, somewhat stabilizing the situation in Gaul and in Hispania. He relied heavily on his forces of Huns. With a ferocity celebrated centuries later in the Nibelungenlied, the Huns slaughtered many Burgundiones on the middle Rhine, re-establishing the survivors as Roman allies, the first Kingdom of the Burgundians. This may have returned some sort of Roman authority to Trier. Eastern troops reinforced Carthage, temporarily halting the Vandals, who in 435 agreed to limit themselves to Numidia and leave the most fertile parts of North Africa in peace. Aetius concentrated his limited military resources to defeat the Visigoths again, and his diplomacy restored a degree of order to Hispania. However, his general Litorius was badly defeated by the Visigoths at Toulouse, and a new Suevic king, Rechiar, began vigorous assaults on what remained of Roman Hispania. At one point Rechiar even allied with Bagaudae. These were Romans not under imperial control; some of their reasons for rebellion may be indicated by the remarks of a Roman captive under Attila who was happy in his lot, giving a lively account of "the vices of a declining empire, of which he had so long been the victim; the cruel absurdity of the Roman princes, unable to protect their subjects against the public enemy, unwilling to trust them with arms for their own defence; the intolerable weight of taxes, rendered still more oppressive by the intricate or arbitrary modes of collection; the obscurity of numerous and contradictory laws; the tedious and expensive forms of judicial proceedings; the partial administration of justice; and the universal corruption, which increased the influence of the rich, and aggravated the misfortunes of the poor."

Vegetius 's advice on re-forming an effective army may be dated to the early 430s, (though a date in the 390s has also been suggested). He identified many deficiencies in the military, especially mentioning that the soldiers were no longer properly equipped:

From the foundation of the city till the reign of the Emperor Gratian, the foot wore cuirasses and helmets. But negligence and sloth having by degrees introduced a total relaxation of discipline, the soldiers began to think their armor too heavy, as they seldom put it on. They first requested leave from the Emperor to lay aside the cuirass and afterwards the helmet. In consequence of this, our troops in their engagements with the Goths were often overwhelmed with their showers of arrows. Nor was the necessity of obliging the infantry to resume their cuirasses and helmets discovered, notwithstanding such repeated defeats, which brought on the destruction of so many great cities. Troops, defenseless and exposed to all the weapons of the enemy, are more disposed to fly than fight. What can be expected from a foot-archer without cuirass or helmet, who cannot hold at once his bow and shield; or from the ensigns whose bodies are naked, and who cannot at the same time carry a shield and the colors? The foot soldier finds the weight of a cuirass and even of a helmet intolerable. This is because he is so seldom exercised and rarely puts them on.

A religious polemic of about this time complains bitterly of the oppression and extortion suffered by all but the richest Romans. Many wished to flee to the Bagaudae or even to foul-smelling barbarians. "Although these men differ in customs and language from those with whom they have taken refuge, and are unaccustomed too, if I may say so, to the nauseous odor of the bodies and clothing of the barbarians, yet they prefer the strange life they find there to the injustice rife among the Romans. So you find men passing over everywhere, now to the Goths, now to the Bagaudae, or whatever other barbarians have established their power anywhere... We call those men rebels and utterly abandoned, whom we ourselves have forced into crime. For by what other causes were they made Bagaudae save by our unjust acts, the wicked decisions of the magistrates, the proscription and extortion of those who have turned the public exactions to the increase of their private fortunes and made the tax indictions their opportunity for plunder?"

Gildas, a 6th-century monk and author of De Excidio et Conquestu Britanniae, wrote that "In the respite from devastation, the island was so flooded with abundance of goods that no previous age had known the like of it. Alongside there grew luxury." Nevertheless, effective imperial protection from barbarian ravages was eagerly sought. About this time authorities in Britannia asked Aetius for help: "'To Aetius, thrice consul: the groans of the British.' Further on came this complaint: 'The barbarians push us back to the sea, the sea pushes us back to the barbarians; between these two kinds of death, we are either drowned or slaughtered.' But they got no help in return."

The Visigoths passed another waymark on their journey to full independence; they made their own foreign policy, sending princesses to make (rather unsuccessful) marriage alliances with Rechiar of the Sueves and with Huneric, son of the Vandal king Genseric.

In 439, the Vandals moved eastward, temporarily abandoning Numidia. They captured Carthage, where they established the Vandal Kingdom, an independent state with a powerful navy. This brought immediate financial crisis to the Western Empire. The diocese of Africa was prosperous, normally required few troops to keep it secure, contributed large tax revenues, and exported wheat to feed Rome and many other areas. Roman troops assembled in Sicily, but the planned counter-attack never happened. Huns attacked the Eastern empire, and "the troops, which had been sent against Genseric, were hastily recalled from Sicily; the garrisons, on the side of Persia, were exhausted; and a military force was collected in Europe, formidable by their arms and numbers, if the generals had understood the science of command, and the soldiers the duty of obedience. The armies of the Eastern empire were vanquished in three successive engagements... From the Hellespont to Thermopylae, and the suburbs of Constantinople, ravaged, without resistance, and without mercy, the provinces of Thrace and Macedonia" Attila's invasions of the East were stopped by the Theodosian Walls; at this heavily fortified Eastern end of the Mediterranean there were no significant barbarian invasions across the sea into the rich southerly areas of Anatolia, the Levant, and Egypt. Despite internal and external threats, and more religious discord than the West, these provinces remained prosperous contributors to tax revenue; despite the ravages of Attila's armies and the extortions of his peace treaties, tax revenue generally continued to be adequate for the essential state functions of the Eastern empire.

Genseric settled his Vandals as landowners. In 442, he was able to negotiate very favourable peace terms with the Western court. He kept his latest gains and his eldest son Huneric was honoured by betrothal to Valentinian III's daughter Eudocia. She carried the legitimacy of the conjoined Valentinianic and Theodosian dynasties. Huneric's Gothic wife was suspected of trying to poison her father-in-law Genseric; he sent her home without her nose or ears, and his Gothic alliance came to an early end. The Romans regained Numidia, and Rome again received a grain supply from Africa.

The losses of income from the Diocese of Africa were equivalent to the costs of nearly 40,000 infantry or over 20,000 cavalry. The imperial regime had to increase taxes. Despite admitting that the peasantry could pay no more, and that a sufficient army could not be raised, the imperial regime protected the interests of landowners displaced from Africa and allowed wealthy individuals to avoid taxes.