Murad I
The Turks defeated the Serbian army in one crucial battle: on the banks of the river Maritsa in 1371, where the forces of Vukašin and Jovan Uglješa Mrnjavčević from today's Northern Macedonia were defeated, destroying any hope for a reunified Serbian Empire. From then on, the Serbian state was on the defensive, and this war culminated in the Battle of Kosovo in 1389. This battle pitted Lazar of Serbia, Vuk Branković, and Vlatko Vuković against the best troops of Sultan Murad I. Both Sultan Murad I and Prince Lazar lost their lives in this inconclusive bloodbath.