The Ottoman Turks (or Osmanlı Turks) were the Turkish-speaking population of the Ottoman Empire who formed the base of the state's military and ruling classes. Reliable information about the early history of Ottoman Turks is scarce, but they take their Turkish name, Osmanlı (corrupted in European languages as "Ottoman"), from the house of Osman I (reigned ca. 1299-1326), the founder of the dynasty which ruled the Ottoman empire during its 620-year history. After the expansion from its home in Bithynia, the Ottoman principality began incorporating both other Turkish-speaking Muslims and non-Turkish Christians, becoming the Ottoman Turks and ultimately the Turks of the present. The Ottoman Turks blocked all land routes to Europe by conquering the city of Constantinople, the capital city of the Byzantine Empire. Hence the Europeans had to find other ways to trade with Eastern countries.

The "Ottomans" became first known to the West in 1227 when they migrated westward into the Seljuk Empire, in Anatolia. However, the Ottoman Turks would create a state in Western Anatolia under Ertugrul, the capital of which was Sögüt; near Bursa to the south of the Marmara, the body of water between the Black Sea and the Aegean Sea. Ertugrul established a principality, as part of the decaying Seljuk empire. His son Osman expanded the principality; and for him, both the empire and the people were named by Europeans as "Ottomans". Osman's son Orhan expanded the growing empire, taking Nicaea, present-day Iznik, and crossed the Dardanelles strait, in 1362. But the Ottoman Empire came into its own when Mehmed II captured the Byzantine Empire's capital, Constantinople (Istanbul), in 1453.