Ottoman Empire
Several historians such as British historian Edward Gibbon and the Greek historian Dimitri Kitzikis have argued that after the fall of Constantinople, the Ottoman state took over the machinery of the Roman state, and that in essence the Ottoman Empire was a continuation of the Eastern Roman Empire under a thin Turkish Islamic guise. Kitzikis called the Ottoman state "a Greek-Turkish condominium". The American historian Speros Vryonis wrote that the Ottoman state was centered on "a Byzantine-Balkan base with a veneer of the Turkish language and the Islamic religion". Other historians have followed the lead of the Austrian historian Paul Wittek who emphasized the Islamic character of the Ottoman state, seeing the Ottoman state as a "Jihad state" dedicated to expanding the world of Islam. Another group of historians led by the Turkish historian M. Fuat Koprulu championed the ""gazi" thesis" that saw the Ottoman state as a continuation of the way of life of the nomadic Turkic tribes who had come from East Asia to Anatolia via Central Asia and the Middle East on a much larger scale, and argued that the most important cultural influences on the Ottoman state came from Persia. More recently, the American historian Heath Lowry called the Ottoman state a "predatory confederacy" led in equal parts by Turks and Greeks converted to Islam.
Ottoman Empire
Muslim sects regarded as heretical, such as the Druze, Ismailis, Alevis, and Alawites, ranked below Jews and Christians. In 1514, Sultan Selim I ordered the massacre of 40,000 Anatolian Alevis ("Qizilbash"), whom he considered a fifth column for the rival Safavid empire. Selim was also responsible for an unprecedented and rapid expansion of the Ottoman Empire into the Middle East, especially through his conquest of the entire Mamluk Sultanate of Egypt. With these conquests, Selim further solidified the Ottoman claim for being an Islamic caliphate, although Ottoman sultans had been claiming the title of caliph since the 14th century starting with Murad I (reigned 1362 to 1389). The caliphate would remain held by Ottoman sultans for the rest of the office's duration, which ended with its abolition on 3 March 1924 by the Grand National Assembly of Turkey and the exile of the last caliph, Abdülmecid II, to France.