This volume has been almost exclusively concerned with religion, and with Gibbon's involvement in its history. It has been only marginally concerned with empire, and not at all with barbarism – though introduced by a passage from the Decline and Fall in which Gibbon remarks on the triumph of Christianity among the incoming barbarians as well as the settled populations of the empire. These themes will need to be resumed.

In concluding Barbarians, Savages and Empires – the fourth volume of Barbarism and Religion – the reader was advised that the present volume would be followed by a sixth, intended to conclude the series and provisionally entitled The Redefinition of Europe (a title which will probably survive as the heading of a section). The series will arrive at the end of the volumes Gibbon published in 1781, when he reached what he considered the fall of the Roman empire in the west and most of his readers have considered the end or climax of the Decline and Fall as they are concerned with it. In his narrative, the concept of ‘Europe’ will be seen moving west with the barbarians, as they ascend the Danube valley, break down the Rhine frontier, and become dominant in Gaul, Britain, upper Italy, Spain and Africa. Gibbon can be seen considering how the Roman and barbaric histories of these provinces can be brought together as constituting the history of ‘Europe’ as that term has been used from his time to ours.