Since Murad had been killed in the Battle of Kosovo, Beyazid decided to avenge his death by massacring the Serbs. Nevertheless, he was able to conclude a treaty with their leader, Stephen Bulcovic[?], and granted Serbia considerable autonomy. Two years later, in 1391, he overwhelmed Byzantine emperor John V Palaeologus, but in the same spirit of reconcilliation, he appointed his son and heir, Manuel, Groom of the Chamber.
With the surrender of Constantinople itself, Beyazid assumed the title of Heir to the Caesars. This was perceived as a serious threat by the Christian rulers of Europe, and a new Crusade was organized to defeat him. The Christian allies, under the leadership of Hungary and Venice, reached the city of Nicopolis[?] in Bulgaria, where Beyazid was waiting for them. He crushed their armies and returned to Constantinople, where a new threat was waiting in the east.
The Mongol warlord Timur Lenk had succeeded in rousing the local kingdoms that had been conquered by the Turks to join him in his attack on Beyazid. In the fateful Battle of Ankara[?], on July 20, 1402, Beyazid was captured by Timur and kept chained in a cage as a trophy. There are many stories about Beyazid's captivity, including one that describes how Timur used him as a footstool. One year later, Beyazid died -- some accounts claim that he committed suicide.
1389 to 1402