This, it should be observed, was the western limit of Turkish expansion in the mass. Azerbaijan is the nearest region to us in which Turki blood predominates, and the westernmost province of the true Turk homeland. All Turks who have passed thence into Hither Asia have come in comparatively small detachments, as minorities to alien majorities. They have invaded as groups of nomads seeking vacant pasturage, or as bands of military adventurers who, first offering their swords to princes of the elder peoples, have subsequently, on several occasions and in several localities, imposed themselves on their former masters. To the first category belong all those Turcoman, Avshar, Yuruk, and other Turki tribes, which filtered over the Euphrates into unoccupied or sparsely inhabited parts of Syria and Asia Minor from the seventh century onwards, and survive to this day in isolated patches, distinguished from the mass of the local populations, partly by an ineradicable instinct for nomadic life, partly by retention of the pre-Islamic beliefs and practices of the first immigrants. In the second category—military adventurers—fall, for example, the Turkish praetorians who made and unmade not less than four caliphs at Bagdad in the ninth century, and that bold _condottiere_, Ahmed ibn Tulun, who captured a throne at Cairo. Even Christian emperors availed themselves of these stout fighters. Theophilus of Constantinople anticipated the Ottoman invasion of Europe by some five hundred years when he established Vardariote Turks in Macedonia.