Battle of Tripolje The Battle of Tripolje took place in November 1402 between the Serbian Despotate and the Brankovic family . The Brankovic family , who were attempting to seize the Serbian throne for themselves , entered the battle along with Ottoman troops given to them by Suleiman , and were decisively defeated by Stefan Lazarević . The Serbian Lazarevic army had come from Zeta ( in modern - day Montenegro ) . A local Serb lord , Đurađ II of the Balšić dynasty , the Despot ' s brother - in - law , had prepared the Despot for establishment of his rule on the field of battle as well . Background . Open conflict between Lazarević and Branković , started a few months earlier , during their stay in Constantinople . They were returning home after the battle of Ankara in which they participated as vassals of the Ottoman sultans . Đurađ Branković , on the order of Stefan Lazarević , was imprisoned in the dungeon . The real reason is not known , but most likely it was the Đurad ’ s plan to approach Süleyman Çelebi , one of the sons of Sultan Bayezid I who fought for the throne . After Lazarević left Constantinople with the ships , Đurađ managed to escape from prison and went to Süleyman . Süleyman gave him auxiliary force in order to stop Stefan ’ s return to his country . With these troops and with his own forces , Đurađ blocked all the main roads throughout Kosovo and Metohia . He expected brothers to return from Zeta . Süleyman didn ’ t trust Đurađ and sent his own commander to command Ottoman forces and to oversee Đurađ . Stefan and Vuk had about 260 man who traveled with them . They were reinforced with the forces of Đurađ Balšić , who was married with their sister Jelena . Their mother Milica also sent some military detachments from Serbia . Using side roads , they traveled from Bar across Shkodër and reached Gračanica in Kosovo , where they met with rest of their forces . The battle . Lazarević ’ s and Branković ’ s forces clashed on 21 . November at Tripolje , near Gračanica . Despot Stefan divided his forces . His brother Vuk commanded the main part of the army who attacked Đurađ ’ s forces , while he commanded smaller part and attacked Ottomans . Stefan ’ s forces managed to rout Ottomans and the big part that event played kesar Uglješa Vlatković , who was in the ranks of the Ottoman forces as their vassal . He told Stefan all about Ottoman battle plans and he spread the stories among Ottomans of how Stefan ’ s forces were powerful . This caused drop of the moral among Ottoman soldiers and when the battle started he crossed to the Stefan ’ s side . On the other side Vuk Lazarević has been suppressed , but ultimately battle has been ended with the Branković ' s defeat . Aftermath . After the battle , Lazarević brothers went to Novo Brdo . In Novo Brdo , there was verbal confrontation between Stefan and Vuk . Stefan was angry at Vuk ’ s ignorance in the art of war and high casualties in the Vuk ’ s rank . This confrontation had high impact on their relationship and would later lead to open conflict between them . Because of his great contribution in battle , Stefan confirmed Uglješa Vlatković ’ s authority over Vranje , Ingošt ( modern - day Surdulica ) and Preševo , also Uglješa became Stefan ’ s vassal . Stefan Lazarević managed to return to Serbia and regain his power . Battle alone started civil war between Lazarević and Branković , who would last for a decade . The war will end in 1412 , when two only remaining representatives of the two families , Stefan and Đurađ , made peace and started together to strengthen Serbia .