In August 1400, Timur Lenk and his horde burned the town of Sivas to the ground and advanced into the mainland. The war culminated at the Battle of Ankara in July 1402.
When Beyazid II was enthroned upon his father's death, he first had to fight his younger brother Cem, who took Inegöl and Bursa and proclaimed himself Sultan of Anatolia. After a battle at Yenişehir, Cem was defeated and fled to Cairo. The very next year he returned, supported by the Mameluks, and took eastern Anatolia, Ankara and Konya but eventually he was beaten and forced to flee to Rhodes.