Bayezid I (Ottoman Turkish: ?????? ????; Turkish: I.
Bayezid, Yildirim Bayezid (nicknamed Yildirim (Ottoman Turkish: ??????), "Lightning, Thunderbolt"); 1354 – 8 March 1403) was the Ottoman Sultan from 1389 to 1402.
He was the son of Murad I and Gülçiçek Hatun.
He built one of the largest armies in the known world at the time and unsuccessfully besieged Constantinople.
He adopted the title of Sultan-i Rûm, Rûm being an old Islamic name for the Roman Empire.
He decisively defeated the Crusaders at Nicopolis (in modern Bulgaria) in 1396, and was himself defeated and captured by Timur at the Battle of Ankara in 1402 and died in captivity in March 1403, triggering the Ottoman Interregnum.