Much of the Serbian nobility had been destroyed by the Ottomans in the Battle of Maritsa. Prince Lazar, ruler of the northern part of the former empire (of Moravian Serbia), was aware of the Ottoman threat and began diplomatic and military preparations for a campaign against them. The Battle of Kosovo took place on 15 June 1389 between an army led by the Serbian Prince Lazar Hrebeljanović and an invading army of the Ottoman Empire under the command of Sultan Murad Hüdavendigâr. The battle was fought on the Kosovo field in the territory ruled by Serbian nobleman Vuk Branković, in what is today Kosovo, about 5 kilometers (3.1 mi) northwest of the modern city of Pristina. The army under Prince Lazar consisted of his own troops, a contingent led by 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 Branković ruled the District of Branković and other areas, recognizing Lazar as his overlord.

Reliable historical accounts of the battle are scarce. The bulk of both armies were wiped out, and Lazar and Murad were killed. However, Serbian manpower was depleted and had no capacity to field large armies against future Ottoman campaigns, which relied on new reserve forces from Anatolia. Consequently, the Serbian principalities that were not already Ottoman vassals, became so in the following years.