The Siege of Constantinople of 1411 occurred during the Ottoman Interregnum, or Ottoman Civil War,[1] (20 July 1402 – 5 July 1413), when chaos reigned in the Ottoman Empire following the defeat of Sultan Bayezid I by the Central Asian warlord Timur. Although Mehmed Çelebi was confirmed as sultan by Timur after the Battle of Ankara, his brothers İsa Çelebi, Musa Çelebi, Süleyman Çelebi, and later, Mustafa Çelebi, refused to recognize his authority, each claiming the throne for himself.[2] A civil war was the result.