Byzantium thus possessed an effective military organization, based upon an efficient and, above all, highly centralized fiscal system. An intelligent, effective and flexible diplomatic and political strategy, combined with a powerful sense of its own identity and the values it represented, enabled it to survive, even flourish, in a highly disadvantageous strategic situation for some six centuries. Its political and military demise followed inevitably from the combination of a series of factors during the twelfth century and after: first, a long-term change in the international political situation, which saw the appearance to the north and west of a number of rival, and often hostile, political formations of equivalent technological, organizational and, above all, economic potential, a situation that had not arisen before this time; second, the loss of the Taurus- Anti-Taurus ranges as a natural political barrier in the southeast, as it was outflanked by the Turkish occupation of Asia Minor from the east in the later eleventh century; third, and perhaps most importantly, major changes in the distribution of political and economic power within the empire, as the growth of a self-aware political, economic and cultural elite challenged the government’s absolute authority over the distribution and consumption of provincial resources. Together, these factors weakened the military organization of the state in the short term, reduced the government’s ability to respond to external threats by an appropriate manipulation of resources in both the short and long term, and created a competition for central power within the elite— with consequent consumption of precious resources in internecine conflicts— which fatally weakened the government’s ability to maintain a consistent foreign policy and defensive strategy. Most of the results of these developments become apparent only during the thirteenth century, but the last fifteen or so years of the twelfth century, culminating in the Fourth Crusade and the partition of the empire, point the way of things to come.
The effects of constant warfare, of the ever-present need to maintain a substantial military force with which to defend itself, were felt directly by the mass of the ordinary people of the empire in particular, and especially by the peasantry who constituted the greater part of the population. For it was they who bore the burden of maintaining these forces, whose lives were in part regulated by the timetable and often exceedingly oppressive, if not ruinous, demands of the state’s fiscal apparatus, quite apart from the effects of warfare and raiding on the provincial economies of the empire at different times. Byzantine society was thus moulded in its institutional forms and in the ways in which it could evolve and develop by factors associated with warfare, and this gives the study of its military and corresponding fiscal organization a particular importance. Byzantium was a society organized for war, yet it was not, in its general aspect, a warlike society, at least not in any traditional sense. It was a society in which the language and vocabulary of warfare permeated both secular and religious literature as well as oral culture in various ways, yet in which warfare was universally seen as evil, even by the soldiers most actively involved. It was also a society which knew what it was defending, and why; and herein, perhaps, is to be found the psychological aspect of its success. The strength of the imperial ideology, in the various forms through which it was effective in society as a whole, was crucial. The certainties which this system of beliefs and values presented to the literate cultural and political elite, the close relationship between the church, as the formal representative of Orthodox Christianity—firmly rooted in the hear ts and minds of the ordinary population—and the emperors, and the ideological motivation thus generated to maintain the state in existence, certainly bear some of the credit for the survival of the East Roman empire. Together with the factors already outlined, this made the East Roman state, with its armies, its military administration and its methods of waging and avoiding warfare, such a significant actor on the medieval historical stage for so long.