We need glance but briefly at these later crusades. The fourth was undertaken in 1203. Venice contracted to transport its warriors to the Holy Land, but instead persuaded them to join her in an attack upon the decrepit Empire of the East.[9] Constantinople fell before their assault and received a Norman emperor, nor did the religious zeal of these particular followers of the cross ever carry them farther on their original errand. They were content to establish themselves as kings, dukes, and counts in their unexpected empire. Some of the little Frankish states thus created lasted for over two centuries, though the central power at Constantinople was regained by the Greek emperors of the east in 1261.[10] Meanwhile the patriotic and powerful King Andrew of Hungary led a fifth crusade. The German Emperor, Frederick II, headed a sixth in which, by diplomacy rather than arms, he temporarily regained Jerusalem.[11] For a time this treaty of peace deprived of their occupation the orders of religious knighthood still warring in the East. One of these, the Teutonic Knights, made friends with Frederick, and by his aid its members were transported to the eastern frontier of Germany, where among the Poles and Po-russians (Prussians) they could still find heathen fighting to their taste. From this order sprang the military basis of modern Prussia.[12] The Seventh and Eighth crusades were the work of the great French King and saint, Louis IX. The enthusiasm which had roused the mass of ordinary men to these vast destructive outpourings was faded. Louis had to coax and persuade his people to follow him, and even his earnest purpose and real ability could not save his expeditions from disastrous failure. In the Seventh Crusade he attacked, not Jerusalem, but Egypt, then the centre of Mahometan power. He was defeated and made prisoner; his army was practically exterminated. Yet by a personal heroism, which shone even more brilliantly in adversity than in success, he has won lasting fame. His captivity disrupted an empire. The mamelukes, the slave soldiers of Egypt, who had fought most valiantly against him, were wakened to a realization of their own power. They overthrew their sultan, and founded an Egyptian government which lasted until Napoleon's time.[13]