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.
Ottomanism
Ottomanism was a form of nationalism, likely inspired and created as a reaction to European ideas of nationalism and the growing Western involvement in the Ottoman Empire. Following the Tanzimat reforms, Ottomanism developed of a need to bring the Empire together. The Ottomans feared the growing threat the Europeans posed, especially after events like the Treaty of Balta Liman that allowed for British merchants in the Empire to be taxed equally to the locals, and the growing concern of the Great Powers over the treatment of Christians and Jews within the Empire. The Ottomans thought that if they could unite the Empire fully under one state entity, then they would be stronger and the Europeans would have a harder time encroaching on Ottoman territory, as well as Ottoman people. Previously, the empire was vastly split into many small communities that mostly governed themselves. The Sultan oversaw these communities, however most adhered to their own laws and beliefs. This was a reason the Ottoman Empire was so successful, because the Sultan didn't force any major changes on populations as he conquered them. Though because of nationalism, the rise of nation-states with shared senses of identities began to rise in Europe, most notably with the Greek War of Independence which also started affecting the Ottoman Empire. From these instances Ottomanism was developed as a social and political response, and a hope to help save the Empire from its downfall.