THE SEVENTH CENTURY, which saw the life of Mul:J_ammad and the Arab victories which deprived the Byzantine Empire of such a high proportion of its territories, is traditionally regarded by Byzantinists as a dark age. It was certainly marked by the profoundest social, economic, and administrative changes which had taken place in the eastern Empire since the third century AD, or even since its very beginning. These changes had many causes, of which the coming of Islam was only one, even if one of the most dynamic; but their impact was indeed felt very forcibly in the eastern provinces of the Byzantine Empire, where contact with Muslims had been preceded by a century of heightened religious tension and rivalry, intensified by an increasing dissatisfaction in many quarters with rule from Constantinople. We are also gradually obtaining archaeological evidence from a broad range of sites which with increasing clarity indicates substantial changes in the traditional urban culture of classical antiquity, even before the Arab conquests; and while this evidence is often difficult to interpret, the overall message is clear enough. In the papers by both John Haldan and Michael Whitby in this volume, the particular characteristics of Byzantine writing in the seventh century are rightly connected with these general developments. I shall be making the same connection in mine, while at the same time arguing that the Arab invasions and subsequent contacts with the new rival faith of Islam provided special and additional stimuli.

Without going into detail, it might be helpful to mention briefly the factors which were already bringing about social change in the Byzantine Empire at the time of the Arab conquests. One such factor was certainly the demographic effects of the great epidemic of bubonic plague which swept Constantinople and the eastern provinces in 542, and which returned in ‘successive waves throughout the sixth and seventh centuries and midway into the eighth. Impossible though it is to quantify the mortality, since we only have the impressionistic accounts of literary sources, the effect on the population must have been great; in Constantinople itself plague mortality and long-term population effects must lie behind the catastrophic drop in population which took place between the sixth century and the eighth. In addition, Justinian's wars, still going on when the plague first struck, proved a very serious drain on manpower and finance. His successors managed to continue the war effort to some extent at least on the Persian front, but Heraclius’ campaigns required intensive and difficult recruitment and fund-raising; it was then that the fundamental restructuring of the Byzantine military system seems to have begun. As the new system was closely tied to land tenure its replacement had implications for the survival of the old landowning, provincial aristocracy, which had hitherto maintained secular culture; moreover, hand in hand with the military changes went basic alterations to the administrative structure of the Empire-again with profound implications for the educational system and the transmission of traditional secular culture.