He succeeded his father Murad I and absorbed rival Turkish principalities in western Asia Minor, took Trnovo in Bulgaria (1393), and Thessaloniki in Greece (1394), blockaded Constantinople (1394–1401), and defeated a Christian army at Nicopolis in 1396. His thrust into eastern Asia Minor, however, brought him to disaster at Ankara in 1402, and he died a captive of his conqueror, Tamerlane.