OVERVIEW

IF AT THE END OF THE FIRST MILLENNIUM of the Christian calendar the state of the known world did not appear fundamentally different from its condition a hundred years before, with the greatest threat at Rome, Aachen, León or Constantinople appearing still to lie with Islam, by the year 1100 the balance had changed perceptibly. The disintegration of the splendid caliphate of Córdoba into numerous squabbling petty kingdoms created the opportunity for a significant expansion of the Christian states. By the end of the century the Muslim cities of central Spain had fallen into Christian hands. At the same time, in the east, the pre-eminent position of the Byzantine empire crumbled. The victory of the Seljuk Turks at Manzikert (now Malazgirt) in 1071, unlike previous Byzantine military disasters, entailed the loss of most of Asia Minor. Despite the best efforts of the Comnenian dynasty that took over the shaken empire, the greater part of this immense territory proved to have been lost forever. The political power of Constantinople would never again rise to the level it had known in the year 1000. Instead, it would be the rulers of western Europe who would answer the pope's call for a crusade to rescue the holy places in 1095, and in the ensuing clash with the Muslim rulers of the Middle East would generate important developments in the attack and defence of fortifications.

Elsewhere in Europe, the claim of the German kings to a dominant imperial status would hit a serious obstacle in the refusal of the popes to continue old practices in which the Church was an adjunct of secular rule. The ensuing conflicts provided great opportunities for the enemies of the new Salian dynasty. Among those drawn more or less willingly into the cauldron were the Norman adventurers, who dramatically imposed themselves as rulers of the assorted peoples of southern Italy, overcoming in the process Lombard petty rulers, Byzantine provinces and Arab powers. Expanding in all directions, these Norman conquerors drew on the civilisations they had taken over to produce, in the following century, a splendid new kingdom, and one that did not distinguish between the religions of its neighbours in taking advantage of weaknesses to push out its boundaries.