The Battle of Kosovo (Serbian: Косовска битка/Kosovska bitka, Turkish: Kosova Meydan Muharebesi) took place on 15 June 1389 between the army led by the Serbian Prince Lazar Hrebeljanović, and the invading army of the Ottoman Empire under the command of Sultan Murad Hüdavendigâr. The army under Prince Lazar consisted of his own troops, a contingent led by Serbian nobleman Vuk Branković, and a contingent sent from Bosnia by King Tvrtko I, commanded by Vlatko Vuković. Prince Lazar was the ruler of Moravian Serbia, and the most powerful among the Serbian regional lords of the time, while Vuk Branković ruled District of Branković located in a part of Kosovo and other areas, recognizing Lazar as his overlord. The battle was fought on the in Kosovo field, in the territory ruled by Branković, in Kosovo. Its site is about 5 kilometers northwest of the modern city of Prishtina.
It is difficult to assess the importance of the Kosovo Battle for world history. However, it is undeniable that the Battle of Kosovo was exceptionally significant not only for Serbia, but also for Europe and European Christian civilization.
It is a fact that on Vidovdan, June 15, 1389, the Serbs, without help from a single European nation, defended on Kosovo Field not only the frontiers of their own territory and lives of their people, but, at the risk of losing their national independence, they also defended the interests and security of Christian Europe. In the conflict of 2 rival civilizations, the Muslim and the Christian, the Serbs checked the wave of the Turkish invasion, interposed themselves as a wall between the Turks and Europe, and enabled Europe to make preparations for its own defense. It is questionable whether the history of Europe would have been the same without the Battle of Kosovo.
Reliable historical accounts of the battle are scarce. We still don't know who exactly won the battle. At one point, the bells of the Notre Dame cathedral in Paris rang out in (maybe) erroneous salute to the Serbs' victory. But even if Serbs won the battle it was a pyrrhic victory.
Both armies were decimated out in the battle; both Lazar and Murad lost their lives, and the remnants of their armies eventually retreated from the battlefield. Murad's son Bayezid strangled his younger brother Yakub Çelebi upon hearing that their father had died, becoming the sole heir to the Ottoman throne. The Serbs were left with too few men to defend their lands effectively, while the Turks had many more troops in the east. Consequently, the Serbian principalities that were not already Ottoman vassals became so in the following years, one by one. Furthermore, in response to Ottoman pressure, some Serbian noblemen wed their daughters, including the daughter of Prince Lazar, to Bayezid. In the wake of these marriages, Stefan Lazarević became a loyal ally of Bayezid, going on to contribute significant forces to many of Bayezid's future military engagements, including the Battle of Nicopolis. Eventually, the Serbian Despotate would, on numerous occasions, attempt to defeat the Ottomans in conjunction with the Hungarians until its final defeat in 1459 and again in 1540.