BAYEZID I. (1347-1403), Ottoman sultan, surnamed YILDERIM or "LIGHTNING," from the great rapidity of his move ments, succeeded his father, 1e1urad I., on the latter's assassina tion on the field of Kossovo, 1389, and signalized his accession by ordering at once the execution of his brother Yakub, who had dis tinguished himself in the battle. He was the first Ottoman sovereign to be styled "sultan." After routing the chivalry of Christendom at the battle of Nikopoli in 1396, he attacked Greece, and Constantinople would doubtless have fallen before his attack had not the emperor Manuel Palaeologus bought him off by timely concessions, which reduced him practically to the position of Bayezid's vassal. He met with an overpowering check at the hands of Timur (Tamerlane). Utterly defeated at Angora by the Mongol invader, Bayezid became his prisoner and died in cap tivity some months later.
Bayezid married Devlet Shah Khatun, a daughter of the prince of Kermian, who brought him in dowry Kutaiah and its depend encies.