Bayezid I 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 1396, and was himself defeated and captured by Timur at the Battle of Ankara in 1402 and died in captivity in March 1403.