The Ottoman rulers masterfully combined military prowess with state-building skills. Having adopted Persian bureaucratic institutions, at the same time they maintained such typical Turkic traits as the nomadic warrior ethos, religious tolerance, and the institution of slave soldiers. To their Greek and Slavic subjects in the Balkans, the Ottoman sultans appealed as a viable (and more successful) alternative to the Roman/Byzantine emperors; to Arab subjects in the Middle East, they were the legitimate successors of the first caliphs. Yet in the long run, keeping such distinct traits proved difficult: the more rigid the Ottoman rulers were in their confessional policy in order to consolidate the Sunni Muslim core of the empire’s population, the more they alienated those who did not belong to this core. The empire’s final decades were characterized by the rising nationalisms and ethnic cleansings whose effects were further deepened by the humanitarian catastrophe related to the wars fought incessantly in the years 1911–1922.