The story of this branch of the Turkish nation is the common story of a people coming West by reason of pressure of other tribes from the East. Mongols, from the borders of China, seem to have been the oppressors, from the East, of the Ottomans. Before the middle of the thirteenth century they were settled near Angora, in what was then called the Kingdom of Rum. It was in the possession of the Seljuk Turks. But the Seljuk kingdom was breaking up. The Greeks of the Eastern Empire were attacking it heavily. The Ottomans, perhaps a hardier people than the Seljuks, because they had more lately been leading the nomadic, wandering life, supported their {219} kinsmen and hosts, and it ended in the Ottomans becoming the leaders of the Turks in Asia Minor. The Greeks were only a little more united and efficient than the Seljuks, and before the middle of the fourteenth century the Ottomans had the whole of Asia Minor in their hands. Their fighting force was much increased by the formation of a standing army, called the Janissaries. They numbered some 12,000 at this time, though this number was more than quadrupled in later centuries. The force was chiefly composed of Christian captives. But these troops had such large privileges allowed them that there was no difficulty in filling their ranks. [Sidenote: Mayors of the Palace] And then happened that which we have seen occurring again and again in course of the story. Just as the Vandals were invited into Africa, just as the Moslems were invited into Spain, and just as both these guests stayed a great deal longer and made themselves much more at home than their hosts had expected, so now the Ottomans were invited into Europe to assist the Mayor of the Palace, as he was called, in Constantinople, who had seized the Government. This title of Mayor of the Palace, for the chief officer or prime minister, was taken from the Frankish court. The power of these Mayors of the Palace became, as we have seen, very great among the Franks, and the office often passed from father to son. The first of the Capets had been Mayor of the Palace to the last Carolingian.