Mehmed I ended the Ottoman Interregnum and reunited the Ottoman state after nearly eleven years of civil war.
The crisis began after Sultan Bayezid I was defeated and captured by Timur at the Battle of Ankara in 1402. Bayezid’s sons—Süleyman, İsa, Musa, and Mehmed—competed for control of the fragmented empire, creating a prolonged succession struggle.
Mehmed Çelebi defeated his final major rival, Musa Çelebi, at the Battle of Çamurlu on 5 July 1413. He then became Sultan Mehmed I and restored central authority over the Ottoman territories. His reign is often viewed as a period of reconstruction after the devastation caused by the civil war.
The other options belong to different periods of Ottoman history. Bayezid I was the sultan whose defeat triggered the Interregnum, while Murad I ruled earlier and Orhan was an early Ottoman ruler. Mehmed I is sometimes called the empire’s “second founder” because of his restoration work.