Either of two battles fought in the Serbian province of Kosovo .
The first (June 13, 1389), between the Serbs under Prince Lazar and the Ottoman Empire led by Sultan Murad I, ended
despite Murad's death
in the defeat of Serbia and the encirclement of the crumbling Byzantine Empire by Ottoman armies. The battle, which led to three centuries of Serbian vassalage, has remained a central event in Serbian history. In the second battle (Oct. 17–20, 1448), between the Ottomans led by Murad II and a Hungarian-Walachian coalition under Hunyadi János , halted the last major effort by Christian Crusaders to free the Balkans from Ottoman rule.