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.
Islam in Turkey
In 1922 the new nationalist regime abolished the Ottoman sultanate, and in 1924 it abolished the caliphate, the religious office that Ottoman sultans had held for four centuries. Thus, for the first time in Islamic history, no ruler claimed spiritual leadership of Islam.
Atatürk and his associates not only abolished certain religious practices and institutions but also questioned the value of religion, preferring to place their trust in science. They regarded organized religion as an anachronism and contrasted it unfavorably with "civilization," which to them meant a rationalist, secular culture. Establishment of secularism in Turkey was not, as it had been in the West, a gradual process of separation of church and state. In the Ottoman Empire, all spheres of life, at least theoretically, had been subject to traditional religious law, and Sunni religious organizations had been part of the state structure. However, usually state had authority over the clergy and religious law, even at the Ottoman period (e.g.many Sultans are known to change Şeyhülislams, who do not approve state politics). When the reformers of the early 1920s opted for a secular state, they removed religion from the sphere of public policy and restricted it exclusively to that of personal morals, behavior, and faith. Although private observance of religious rituals could continue, religion and religious organization were excluded from public life.