Süleyman Çelebi was the son of Ottoman Sultan Beyazid I. After the Timurid capture of his father and brief occupation of Anatolia in 1402/804 AH, Süleyman Çelebi ruled over the Ottoman territories in southeastern Europe and gradually took back portions of Anatolia until he was captured and executed by his brother Musa in 1411/813.

Source:

C. E. Bosworth, "Süleyman Čelebi," in Encyclopaedia of Islam, Second Edition. http://dx.doi.org/10.1163/1573-3912_islam_SIM_7171 [Accessed April 17, 2018].