The final parts of the jigsaw were the Vandals, Alans and Suevi. Constantius now used his peace with the Goths to his advantage. Reinvigorating his Roman army with Gothic allies, he moved south to Spain, defeated the Vandals, Alans and Suevi, and brought the Iberian provinces back under Roman control. In the space of just ten years Constantius had brilliantly extricated the western Roman empire from the crisis that had nearly killed it. He pulled together once more all the threads of the western domains that a decade earlier had looked to be hopelessly untangling, and held them in the grip of his hand. In achieving this brilliant feat, however, there had been a high price to pay.
The years of looting and the ravages of warfare across the west meant that agricultural produce, and hence revenues, were down. With the Goths settled in Gaul, there was a much smaller area of provincial territory able to deliver tax into the imperial coffers. For example, the island of Britain, ignored by Constantius as his army focused on putting out fires in Gaul and Spain, was now detached from the western empire and lost for ever. Henceforth it could not rely on the protection by the western empire’s forces. As a result of such changes, there were few resources to rejuvenate a western army that had been reduced by almost half in the wars against the barbarians during the critical years of Honorius’s reign (395–420). Although the emperor remedied the western army’s huge losses by providing more units, the majority of these were not new field army units, but lower-grade auxiliary units that had been upgraded and reclassified. The money did not stretch far enough for anything more than a military facelift.38
The final hangover from the years of invasion was widespread disaffection among the provincial landowning élites. These were the local self-governing centres of power that organized tax-gathering, and on whom the imperial centre of the west depended for the task’s successful administration. They were not happy, and their disaffection centred on one simple fact. The emperor Honorius had not been able to keep his side of the bargain – to provide military protection for their property in exchange for the collection of taxes. After years of upheaval and diminishing security, it was becoming obvious that the ancient contract between emperor and local élite was slowly being torn up.39
This disaffection could easily turn to outright defiance. The train of thought perhaps ran as follows: if life under a Gothic or Vandal king would prove safer, if it offered the benefits of protection from war, and if it proved more conducive to sustaining their lifestyle, why bother to be part of the Roman empire at all? In the early fifth century cases of local élites breaking away from the centre were isolated, but this could and would become a trend. With five per cent of western Roman citizens owning 80 per cent of the land, the loosening of this old cornerstone of the Roman empire was a critical effect of the barbarian invasions – another hammer blow in the fall of the western empire.
Consequently, despite Constantius’s success, the same forces that had so rattled Italy under the impact of Alaric’s Goths had returned to wreak havoc on the western empire during Constantius’s years of regaining control. Like a convalescent from major surgery, the western empire was now well again, but it was a pale shadow of its former self. Soon it would have to find the strength to stomach further pummellings. The most fatal of these centred on the rich Roman province of Africa, the granary of the western empire.
In 421 Constantius, now appointed co-emperor, fell ill and died unexpectedly. When Honorius passed away two years later, a protracted struggle for power was let loose with one brief regime swiftly falling prey to the bloody cull of another. Eventually, Valentinian III, the six-year-old son of Constantius and Galla Placidia, was promoted to emperor. The real ruler, the man who had actually won the power struggle in 431, was a worthy successor to Constantius. Known as the last great Roman commander, Flavius Aetius had his hands full when he became commander-in-chief of the Roman forces. During the fight for succession, the regrouped and revitalized Vandals had crossed from Tarifa in southern Spain, landed in Africa in May 429 and began heading east. Either by assault or by treaty, they gradually took control of what is now Morocco and Algeria. By 439 they had captured the empire’s third largest city – Carthage. By taking this province, the Vandals had their hands at the west’s jugular.
In the early fifth century, Africa was the chief source of grain and revenue for Rome and Italy. Under Julius Caesar, 50,000 tonnes of grain in a year was shipped from Carthage, and since that time shipments had continued from the massive extended Roman docks there. For this reason Africa was the western empire’s lifeline. Now Aetius set about resuscitating it. During the 430s he had been detained from taking action against the Vandals by a new wave of barbarian invasions and rebellions in the western provinces. By 440, however, he had brought those under control, had won – through brilliant diplomacy – assistance from the eastern empire, and had amassed an extraordinary allied fleet in Sicily. The aim of the united forces of the eastern and western Roman empire was the reconquest of the key province of Africa. However, at the moment when Aetius should have given the order for the 1100-ship fleet to sail, the mission was suddenly abandoned. The eastern forces, said the emperor of the east, were urgently required back in his half of the empire because Constantinople was facing an invasion like no other. The decision to ditch the attack on North Africa would prove to be the last critical turning point in the collapse of the west. The man who had provoked it came from the very same people who, in 376, had sparked the first ‘big bang’ moment in the fall of the west, the first invasion of Rome’s northern frontiers. His name was Attila the Hun.
Just as the Huns began the story of the fall of the western Roman empire, so they end it. During his campaigns of the 430s, Aetius had temporarily engaged the services of the Hunnic forces. However, now, in 440, with their leadership united under Attila and their ascendant empire stretching from the Black Sea to the Baltic and from Germany to the central Asian steppes, the Huns were back for much more than a lucrative military partnership. In two devastating sweeps through the Balkans in 441 and 447, Attila invaded the eastern empire and made a mockery of the Roman army’s resistance. The effectiveness of his forces came down not only to the use of the bow. The Huns were the first barbarian force to work out how to storm well-defended fortress towns. The secret of their success lay in the skilful use of siege engines, battering rams and scaling ladders, which they had simply copied from the Romans. By ransacking the eastern empire in this way, Attila was able to extort incredible amounts of gold out of Constantinople. In 451, however, he received an invitation to lay his hands on new riches. Allegedly enticed by a rescue plea-cum-marriage proposal from the rebellious sister of the emperor Valentinian, Attila turned his attentions to the west.