Peter Heather, The Fall of the Roman Empire: Chapter 5, "The City of God"

After a little scene-setting account of the sack of Rome, and a brief note on original sources (Olympiodorus' history is the best narrative, but it is mostly preserved only in partially garbled extracts by later historians), Heather plunges into describing the new wave of barbarian invasions from 405-410: Radagaisus' Goths over the Danube bend and into Italy in 405/406, the Vandals, Alans, and Suevi across the Rhine into Gaul in 406, Uldin's Huns across the middle Danube in 408, and the Burgundians just across the Rhine around 411. Literary sources arguably suggest that all of these peoples can be placed in Central Europe in the period immediately before the invasion. They also report that these invasions were movements of large numbers of people, including many who were not warriors. Archaeological evidence shows a contemporaneous disappearance of the existing barbarian material culture in these regions. The invasion routes, the barbarian groups involved, the size of the movements, and the disappearance of existing cultures together points to a thoroughgoing displacement of the peoples of the Central European plain as the source of the invasion.


Heather admits that the motive for such a huge, rapid displacement can only be speculative, but he comes down on the side that they were pushed out rather than attacking of their own accord. Invading the empire was a huge risk. Roman hostility could be counted on, and success was far from certain -- a point which could only have been reinforced by the defeat of the first of these invasions, led by Radagaisus, in 406. Moreover, we have a plausible propelling force in the Huns, who had caused large scale movements before, and who are known to have occupied the lands of Central Europe from a time fairly shortly after the invasions.


The Vandals, Alans, and Suevi looted their way across Gaul for three years before moving on to Spain, where they finally settled down and replaced Roman rule with their own. During these barbarian peregrinations, the armies of Britain and Gaul revolted against central rule and settled on Constantine III as their schismatic emperor -- a development which was likely related to the failure of the hard-pressed Roman government under Stilicho to come to their aid.

Stilicho's hands were full not just because of Radagaisus, but even more because the Goths in the empire's Balkan provinces had revolted in 395. These Goths were now united under a single leader, Alaric. Their core concern was extracting a more binding guarantee of their permanent status in the empire. Having failed to extract such an agreement from the Eastern Empire, Alaric turned west, invading Italy in 401-402. But Stilicho was no more amenable to a settlement, and succeeded in fending the incursion off.
But in 406 Stilicho changed his tack, and sought out an agreement with Alaric for an alliance against the Eastern Empire. This would seem to be adding another course to an already overfull plate, but Heather argues that Stilicho's plans show that the real interest was a permanent alliance which would supplement the Roman army in the West with Gothic warriors to deal with the emerging threats to Gaul. The key point for Heather is that Stilicho's aims were limited to bringing all of Illyricum under Western control. This was a scaling back from his previous ambition to rule in the East, but it makes sense in terms of coming to a permanent disposition of the Gothic problem in the Balkans, since it would give him the authority to settle the Goths there.


In the event, the crisis erupted in Gaul before Stilicho could deliver on his promise to send Roman legions to join Alaric in the Balkans. Once barbarians were rampaging across Gaul and Constantine was in revolt, the legions could no longer be spared. Alaric, left in the lurch, moved his Goths to the Alpine passes to extort payment from Stilicho. He got it, but the Roman bureaucrat Olympius' conspiracy overthrew Stilicho soon after, and Rome adopted a policy of open hostility to the Alaric.


The extension of that hostility to Goths within the Roman army, however, led many to defect to Alaric. Supplemented by these forces and (probably Gothic) revolted slaves, Alaric invaded Italy again, laying siege to Rome itself in order to secure a deal. In the end, no deal was forthcoming, and Alaric's Goths finally (albeit respectfully) sacked Rome.


Following up on his description of the sack, Heather notes its profound ideological consequences. It led to a vigorous debate between Christians and pagans -- pagans claiming that the sack happened because Christian Rome had been abandoned by the Gods, while Christians argued that pagan Rome, too, had suffered sack and defeat in its history. Augustine followed through with this argument quite radically in The City of God, arguing essentially that there was nothing special, permanent, or divine about the Roman Empire -- that it was just one state among many others.

In contrast to Augustine's indifference, Heather leads into his account of the recovery of the Western Empire over the next decade with Gallo-Roman writers, Christian and pagan, who held fast to the Roman ideal.

The Roman recovery started with the supply-starved Goths departure from Italy to Gaul in 411, under Alaric's successor Athaulf. This freed the new Roman military commander in the West, Constantius, from concerns about leaving Italy uncovered, so he was finally able to take on the rebel emperor Constantine and his successors in Gaul. Against the last of these successors, Jovinus, Constantius had the assistance of Athaulf's Goths. But Athaulf had larger ambitions of his own -- he even married the Western emperor Honorius' captive sister Galla Placidia -- which got in the way of a more permanent settlement with the Goths. Constantius applied pressure by blockading supplies to the Goths in southern Gaul. By 415, the Goths had had enough: they overthrew Athaulf and came to terms with the Romans. In 416-418, Constantius marched into Spain with his new allies and put paid to the Alans and Siling Vandals (leaving just the Hasding Vandals and Suevi in the northwest to survive) before settling the Goths across the Pyrenees in Aquitaine.

As impressive as Constantius' successes were, the Western Empire was still substantially weaker than it had been fifteen years earlier. Britain and parts of Spain had never been recovered, and the tax revenue from much of Italy and Gaul must have plummeted due to the ravages of the invasions. A contemporary army register shows that half of the first-line units of the Western army had been lost, and only about half of the lost units were replaced with new first-line formations. Events of the last two decades had also shown the political fragility of the empire -- local landed elites were quick to cut deals with barbarian invaders to preserve their status.