The first great city to which the Crusaders came in 1096 was not Jerusalem but Constantinople. Almost as much as Jerusalem itself, Constantinople was the key to the foundation, survival and ultimate eclipse of the crusading kingdom. The Byzantines had developed an ideology over seven hundred years which placed Constantinople, rather than Rome or Jerusalem, at the centre of the world. The attitudes of its rulers reflected this priority, and led to tension with the crusaders over military and diplomatic strategy. At the same time, the riches and sophistication of the great city made a lasting impression on the crusaders. In the end, the lure of the city's wealth was fatal to the claims of Christian unity. In April 1204, the Fourth Crusade under the Venetian doge Enricho Dandolo captured and sacked Constantinople, signalling the effective end of almost a thousand years of Byzantine dominance in the east.