The western empire was to ‘fall’ eighty years later in 476. The ‘fall’ when it came was hardly a major or unexpected event in itself. By the 470s the western emperors had lost control of virtually all their territories outside Italy and relied on German soldiers to lead their own depleted troops. A boy emperor, Romulus ‘Augustulus’, ‘the little Augustus’, was deposed by a Germanic soldier, Odoacer, who then got in touch with the emperor in the east, Zeno, asking for a position as patricius, in effect a high-ranking subordinate with the status of consul. Zeno had hopes that his own nominee for western emperor, one Julius Nepos, who had been expelled from Italy shortly before, might yet be restored so he hesitated. By the time Julius died, unrestored, in 480, Odoacer was firmly in place as ruler of Italy and effective control over the last remnants of the western empire had been lost. (It is good to report that Romulus’ life was spared and there is some evidence that he was still living on a private estate in Italy thirty-five years after his deposition.)
The fall of the western part of the empire has gripped the imagination of later generations. Edward Gibbon’s magnificent Decline and Fall of the Roman Empire must bear some of the responsibility, within the English-speaking world at least, for creating an image of a cataclysmic event in human history that requires some kind of special explanation (although Gibbon was not only concerned with the west and continued the story up to the fall of Constantinople in 1453). Gibbon himself laid the blame on Christianity, which he claimed had undermined the ancient warrior traditions of the Romans and, through the influence of monasticism and asceticism, turned them away from earthly things. He echoed the pagan historian Zosimus, writing in Constantinople about 500, who blamed the fall on the abandonment of sacrifices at the temple of Jupiter in Rome. These speculations do not explain why the east, more fully Christianized than the west, survived.
There have been innumerable other theories—one book lists 500 of them—but behind many of them lurks the assumption that the Roman empire had some magic element, a moral superiority, for instance, which should have protected it for ever against the processes of historical change. The idea is not new. Theodosius I was once told by one local Gallic magnate, ‘We know that no revolution will ever overthrow the state because the Roman empire is fore-ordained to remain with you and your descendants.’ Arguably it was the misplaced confidence in the survival of the empire that left its aristocratic and military leaders unable to conceive the radical alternative strategies needed to save it.
Every explanation, however, must include the fact that the empire in the west faced constant pressures along its extended borders on the Rhine and Danube. By 395 these pressures had lasted over 200 years, ever since the first wars against the Marcomanni in the 160s. What was remarkable was that the Roman armies had managed to hold the borders intact (with the surrender only of Dacia in the third century). The empire had continually found the resources to build forts and raise new armies while in the late third and early fourth century it had undergone a major restructuring under Diocletian and Constantine. Modern scholars have now re-established this period of ‘late antiquity’ as one of vitality and achievement. The old convention by which histories of the Roman empire were allowed to peter out after Diocletian can no longer be sustained.
So what changed in the late fourth century?