554 THE HISTORY OF MEDIEVAL EUROPE her possessions on the coasts of Greece and in the islands of the JEgean. In 1291, however, the Latins lost their last foothold on the coast of Syria to the Moslems. Sometime after the Mongols had receded from the territory which is now Roumania, the two native principalities of Wallachia and Moldavia were founded. They "continued to exist in one form or another until their union under a single ruler in the present century." Under Stephen VI (i33 I_ i355)> Serbia became for a time the chief power in the Balkan peninsula. Stephen extended his sway over Macedonia, Thessaly, Epirus, Albania, Bosnia, and part of Bulgaria; and assumed the title, Emperor of the Romans. In the later Middle Ages the Ottoman Turks, so named from Osman, one of their early leaders, take the place of the R . fth Seljuks of the crusading period, and have re- Ottoman mained a problem of world diplomacy to this day. Their invasion of Europe represents the last we have to consider of those successive waves of mounted Asiatic nomads who, ever since the Huns drove the West Goths across the Danube, had so frequently appeared in medieval history. In the thirteenth century the Ottoman Turks established themselves in Asia Minor and by the first part of the fourteenth century had conquered all the Byzantine possessions in Asia except Trebizond. In the course of time they altered considerably their nomadic mode of life, but they have never shown much capacity for civili- zation. They were great fighters and fanatically devoted to Islam. They were fortunate from the thirteenth to the ; fifteenth century in having sultans of great ability. They themselves preferred to fight on horseback, but they also made much use of the Janizaries — Christian children who were captured and trained to serve as infantry. Presently a civil war broke out in Constantinople and the rival parties not only turned for aid to Serbia, Bulgaria, They enter Venice, and Genoa, but also employed the Otto- mans as mercenaries. The result was that not only Serbia, Bulgaria, and Genoa took for themselves slices of Byzantine territory, but that in 1353-1354 the Turks
