Origin of Ottoman Empire
The Ottoman state began as a small state in western Turkey. The settlers, called Oghuz, had come to Turkey during the Seljuk reign. The Ottomans were perpetually in conflict with other small Muslim states. By and by, they overpowered and absorbed the smaller states thereby ending all other Turkish dynasties.
By 1400, the Ottomans had established their supremacy in the greater part of Anatolia and even extended to the Byzantine territory in Eastern Europe. In 1402, the Ottomans, who by then had moved their capital to Edirne in Europe, made an attempt to access the last bastion of the Byzantine Empire - Constantinople.
The victory over Constantinople would serve a dual purpose. It would not only make a powerful statement of the Ottoman might, it would also give them absolute control over the east-west trade. After a long resistance put up by the Byzantines Constantinople finally fell to Sultan Mehmed in 1453, and was renamed Istanbul. Since then Istanbul has remained the capital of Ottoman Europe. It turned into one of the wealthiest and most cultured cities in Ottoman Turkish history.