Following the weakening of the Anatolian Seljuk State, several beylics from various Turkish tribes emerged in Anatolia. One of these beylics was the Ottoman Beylic, a member of the Kayi tribe of Oghuz Turks from the Sogut-Yenisehir-Bilecik region. The Ottoman Beylic succeeded in establishing the union of the beylics in Anatolia in a short period of time. The Ottomans who fought against the neighboring Byzantine State, first crossed into Rumelia and then captured Constantinople in 1453 during the reign of Sultan Mehmed II (1451-1481), putting an end to the Byzantine Empire and thus, to the Middle Ages. In the reign of Sultan Mehmed II, who assumed the title of "the Conqueror", the Ottoman State entered into an era of rapid development which would last until the end of the sixteenth century. The National War of Independence (1919-1923)
The National War of Independence was an effort to create a new state from the ruins of an Empire which had completed its life. These efforts lasted for four years because the imperialist states wanted to bring to life a new order suitable for their own political aims and interests from the ruins of this empire.
The Turkish resistance movements were transformed into a complete war of independence when Mustafa Kemal landed at Samsun as the Inspector of the 9th Army on 19 May 1919. It achieved success against the armies supported by the large countries of the world and under very difficult conditions.Mustafa Kemal, who joined the Ottoman Army as a captain on 11 January 1905, proved his military talents on almost every front during the First World War. When the Ottoman Empire was considered to be defeated following the First World War, he was appointed Commander of the Lightning Armies. However, when this army was abolished, he returned to Istanbul. Mustafa Kemal, who understood that a political result could not be reached against the occupying powers which were oppressing the Istanbul Government, decided to go to Anatolia and carry on his struggle from there. He immediately started to organize national resistance and got in touch with all the army units and resistance organizations in Anatolia. He made the first call for a national movement with the circular he issued in Amasya on 22 June 1919. The Government of the Turkish Grand National Assembly saved the country from being partitioned and occupied with the National War of Independence. A few months following the signing of the Lausanne Treaty, in which the Allied powers and the world recognized the independence and sovereignty of Turkey. Thus, the Republic was proclaimed on 29 October 1923 in order to give the state a democratic form in the contemporary sense. Mustafa Kemal, the successful and great charismatic leader of the national struggle for independence, was elected unanimously as the first President of the Republic of Turkey.