Bayezid I

Bayezid succeeded his father Murad I at Kosovo in 1389 and earned the name Yildirim, "the Thunderbolt," for the speed of his campaigns. He besieged Constantinople, crushed a European crusade at Nicopolis, and unified much of Anatolia — until Timur destroyed his army at Ankara in 1402 and took him captive. He died in captivity in 1403.

He struggled to hold together a realm expanding on two fronts at once, alienating Anatolian Turkish lords by absorbing their beyliks — a resentment Timur exploited — while pressing the long blockade of Constantinople.

Bayezid is remembered for martial energy and ambition; his defeat, however, became a moral tale in the tradition about the reversal of fortune and the ruin of pride, his captivity under Timur a byword for the fall of the mighty.

He won the crushing victory over the crusaders at Nicopolis (1396) and unified Anatolia by war, but was annihilated and captured by Timur at the Battle of Ankara (1402), which plunged the Ottoman state into a decade-long interregnum.

The story of his captivity — including the legend that Timur carried him in a cage — is partly later embellishment debated by historians. His absorption of fellow-Muslim Anatolian beyliks, and its role in his downfall, is analyzed as strategic overreach.

Bayezid's defeat at Ankara nearly destroyed the young Ottoman Empire, triggering a civil war among his sons; that the state survived and recovered under Mehmed I and Murad II is a measure of how deeply his fall shook it. His reign marks both a height of expansion and its near-collapse.