Murad was succeeded by his son Bayezid I, called ‘Yildirim’, or ‘the Thunderbolt’, who executed his brother to avoid a civil war over the throne (it was the Turkish tradition that a bey divided his country equally among his sons which caused frequent internal struggles between the brothers). The beys of Anatolia revolted on the news of Murad’s death so Bayezid returned East and won resounding victories there (1391); more trouble broke out in the Balkans so he went West again in 1393; he started to blockade Constantinople but a European Crusade was launched against him which he routed in 1396 at Nicopolis: these campaigns earned him great fame as a ghazi throughout the Muslim world.

By the late 1390s, Bayezid was simultaneously waging war on the Mamluks and encroaching on the sphere of influence of the Il-Khanid ruler Timur, in eastern Anatolia, while still pressurising Constantinople. Timur, who saw himself as successor to the first Mongol invaders and descendant of Chinghiz Khan, saw Bayezid still as a simple bey of the marches. He exchanged envoys with the king of France and having secured the support of a worried Europe he went in to action against Bayezid and crushed his army, capturing the Sultan himself at the Battle of Ankara in 1402, and subjecting him to the humiliation of keeping him in a cage.