After the dispersion of Seljuk, Karamanids seemed to be the most powerful state amongst the Turkish states. However, Ottomans who made their center Söğüt, inside the city of Bilecik didn’t take attention. Ghazi Ertugrul was appointed to Byzantine border by the order of Seljuk Sultan Alaeddin. Chieftain Osman (Osman Bey) who took the lead in 1821, declared independence in 1299 and established Ottoman Empire Istanbul was the last capital of Ottomans after being conquered by Sultan Mehmet the Conqueror in 1453 and large lands were administered from here till the 20th century. Time of Suleiman the Magnificent (1520-1566) had the largest state borders. Ottoman Empire protected the large borders until 17th century started to have major "territorial losses after 1700. Ottoman Empire entered the 20th century weakening, and it was governed by the influence of Committee of Union and Progress after the dethronement of Abdul Hamid II in 1909.
The socialite of this party, who had hopes to revert the old lands, entered the World War I with Germany in November 11, 1914. After four years of war, the lands of defeated Ottoman Empire were shared by the intruder forces. War of Independence was initiated under the leadership of Mustafa Kemal Atatürk for Ottomans remained silent to the invasion.
Ottoman Empire century was one of the world's most powerful states in 16th century. Dozens of new states have established on the lands of dispersed empire in the 19th and 20th century. The sultans of this empire who ruled for 600 years belonged to the same family.