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 Europe
Islam entered southern Europe through the invading "Moors" of North Africa in the 8th–10th centuries; Muslim political entities existed firmly in what is today Spain, Portugal, South Italy and Malta for several centuries. The Muslim community in these territories was converted or expelled by the end of the 15th century (see "Reconquista"). Islam expanded into the Caucasus through the Muslim conquest of Persia in the 7th century. The Ottoman Empire expanded into southeastern Europe, invading and conquering huge portions of the Byzantine Empire in the 14th and 15th centuries. Over the centuries, the Ottoman Empire also gradually lost almost all of its European territories, until the empire collapsed in 1922. The countries of the Balkans continue to have large populations of native Muslims, though the majority are secular.