Mehmed I was an Ottoman Sultan known for re-unifying the Ottoman lands of Western Anatolia and Rumelia after the Timurid intervention in Anatolia in 1402/804 AH and subsequent divide in power between himself and his two brothers, Musa and Süleyman Çelebi.
Source:
H. Inalcik, "Mehemmed I," Encyclopaedia of Islam, Second Edition. http://dx.doi.org/10.1163/1573-3912_islam_COM_0728 [Accessed April 17, 2018].