The Ottoman Interregnum continues into its second decade, as the sons of the late Sultan Bayezid fight for control of the empire.

Musa has the support of Wallachians and Serbs and Süleyman has the support of Constantinople, but the Serbs change sides and Musa is defeated in the Battle of Kosmidion on June 15, 1410.

Suleyman is a weak prince, however, and to the dismay of his partisans, he begins living in extravagance.

Mûsa leads Turks and Wallachians against his brother Süleyman, having coaxing Süleyman's Serbian and Bulgarian Janissaries over to his side.

Süleyman’s indifference to state affairs has caused him to lose supporters, especially after the death of his able vizier Çandarlı Ali Pasha.

Thus, when Musa marches to Edirne in 1411, Süleyman has almost no one at his side.

He tries to escape to imperial Greek territories, but Musa captures him and orders his strangulation on February 17, 1411.

Musa now declares himself sultan in Edirne and undertakes the reconquest of the Ottoman territories in Rumelia.

Bedreddin, a convert to Sufism (Islamic mysticism) who had in 1383 undertaken the pilgrimage to Mecca, and, upon his return to Cairo, had been appointed tutor to the Mamluk crown prince of Egypt, had then traveled as a Sufi missionary throughout Asia Minor; his communalistic doctrines have made him a popular preacher.

Mûsa now appoints Bedreddin chief military judge.

Mehmet, upon winning the throne of the Ottoman Empire from his brothers, banishes the Sufi preacher Bedreddin to the Ottoman city of Iznik.

Bedreddin has further refined his doctrines during his exile and maintained contact with a secret society that in 1416 stages a social uprising, of which he becomes the ideological head.

Upon the collapse of the rebellion, he is arrested, and, after a trial of dubious legality, he is convicted and hanged.