In the final paragraph of the last volume of The Decline and Fall of the Roman Empire Edward Gibbon sketched the issues that had most concerned him. In the section of the list which covers the causes of the end of the Roman West one finds “the disorders of military despotism; the rise, establishment, and sects of Christianity; the foundation of Constantinople; the division of the monarchy; the invasion and settlements of the barbarians of Germany and Scythia.” All these issues had certainly attracted Gibbon's attention in previous volumes, although in an even more succinct précis he had placed particular emphasis on two factors: “I have described the triumph of Barbarism and Religion.”

In what follows I wish to examine the relationship between the “triumph of Religion” and the “Decline and Fall” of the west Roman Empire—taking “Decline and Fall” as the period from the fourth to the seventh centuries, and not in a strictly Gibbonian sense. Although one can certainly say that the Empire came to an end in the West at some point in the fifth or sixth century, my prime concern is not with the significance of the deposition of the last western emperor (nor even with the fall of the Empire), but rather with the difference between western Europe, and the western Mediterranean more broadly, in 300 and in 600. While this is not intended as a critique of Gibbon, his interpretation provides a useful scaffolding for examining the changes that took place between those two dates. The distinction between the late- and post-Roman western Mediterranean can be seen as illustrating a “Decline,” but, as will become clear, I doubt whether the qualitative judgement that the word implies is helpful when one considers the major changes that took place.

Even though Gibbon's concerns, most especially that of religion, will provide the main focus for the line of argument that I will put forward, it should be stated immediately that his summary can no longer be regarded as providing an adequate list of the causes of the fall of the west Roman Empire.

The reactions to the devastation of parts of Gaul and Spain, and to the activities of the Visigoths within Italy did, however, have their religious side. Some pagans attributed the taking of Rome by the barbarians in 410 to the aban-donment of the old gods, while some Christians saw the disaster as a just retribution on a sinful world. One need only recall the letters of Jerome and Pelagius, and the sermons of Augustine, written in the immediate aftermath of the Sack of Rome; or the subsequent, and very much more considered, response of the bishop of Hippo in the City of God. Orosius reversed the pagan argument: the destruction had been unleashed by God on the ungrateful city, and indeed the major damage to the forum had been caused by a divine thunderbolt, which destroyed all the idols. Even so, in his view, the three-day sack in 410 was as nothing compared with a fire that had devastated the city 700 years after its foundation (i.e. in 54/53 bc), not to mention the one that lasted six days during the reign of Nero or the total sack of Rome by Brennus following a six-month siege in ca. 399 bc. In any case, the Gothic sack famously morphed into a religious procession after Alaric ordered the restitution of “the sacred vessels” to the Church of St Peter.

It is worth pausing here for a moment on some of the ideas relating to the Empire and its demise that were current in the fourth, fifth, and sixth centuries. Eusebius, of course, had set out a very positive view of the Empire as the fulfilment of Christian history. In one way or another his view was adapted in the East to fit the developments of the fifth century—the reigns of Theodosius II (401–50) and of Marcian could still be seen as belonging to the triumph of the Christian Empire. In the West, despite the fact that Eusebius's Chronicle, in Jerome's translation, seems to have been better known than it was in the East, it was harder to follow a pure Eusebian line. Not surprisingly there is an apocalyptic strain to be found in a number of chronicles of the period, notably that of Bishop Hydatius writing in north-west Spain in the middle of the fifth century.