After winning the Interregnum, Mehmed crowned himself sultan in the Thracian city of Edirne that lay in the European part of the empire (the area dividing the Anatolian and European sides of the empire, Constantinople and the surrounding region, was still held by the Byzantine Empire), becoming Mehmed I.
Furthermore, as a result of the Battle of Ankara and other civil wars, the population of the empire had become unstable and traumatized.