 Complete the following phrase:  An Ottoman army led by Sultan Murad, estimated at between 27000 and 30000 men, arrived in June 1389 on the Kosovo Field near Priština. The Ottomans were met by the forces commanded by Prince Lazar, estimated at between 12000 and 20000 men, which consisted of the princes own troops, Vuk Brankovićs troops, and a contingent sent by the King Tvrtko I of Bosnia. In the Battle of Kosovo, both Prince Lazar and Sultan Murad lost their lives. The battle was tactically inconclusive, but the mutual heavy losses were devastating only for the Serbs, who had brought to Kosovo almost all of their fighting strength. Lazar was succeeded by his eldest son Stefan Lazarević, who became an Ottoman vassal in the summer of 1390. Vuk Branković accepted Ottoman suzerainty in 1392. Stefan Lazarević participated on the Ottoman side in the 