Under John II and Manuel I Byzantium remained a wealthy and expansionist power, maintaining the internal structures and external initiatives which were necessary to sustain a traditional imperial identity in a changing Mediterranean world of crusaders, Turks and Italian merchants. The revival of imperial interest in the crusader states had permanent consequences in that it led to a renewal of Byzantine links with Western Europe. Yet the period following Manuel's death and the overthrow of the regency government of Alexios II saw reversion to something like the isolationism of John II's early years. The Byzantine state was one of the most centralized in the medieval world, and never more so than in the period 1081-1180, when the loss of central and eastern Anatolia forced the empire's military elite, as well as its bureaucratic elite, to identify with the capital as never before. Under the successors of Manuel I, the Comnenian system, centred on Constantinople, was programmed for self-destruction.

At first sight it may seem surprising that the truncated and war-ravaged remnants of the crusader states should have lasted as long as they did. Directly after the Third Crusade there were few places in the Latin Kingdom other than Tyre and Acre that could have held out against full-scale assault. It is difficult to estimate the military resources at the disposal of the rulers of kingdom of Jerusalem in the thirteenth century. The ability of the military Orders to build and garrison substantial fortresses, take a share in the defence of the cities. The ports of the Latin east thus became the entrepots in what was evidently a most lucrative commerce. Trade and the wealth generated by trade were of the utmost importance to the rulers of Latin Syria. In the decades immediately following the Third Crusade the chief theatre of conflict in the east was Antioch.