War with the Bulgarians and Mongols
At the end of the 13th century Bulgarian feudal lords Darman and Kudelin were jointly ruling the region of Braničevo (in modern Serbia) as independent or semi-independent lords. They regularly attacked Stefan Dragutin's Syrmian Kingdom, in Mačva, an area previously under the sovereignty of Elizabeth of Hungary. The Hungarian queen had sent troops to claim Braničevo in 1282–1284, but her forces had been repelled and her vassal lands plundered in retaliation.
Another campaign, this time organized by both Dragutin and Elizabeth, failed to conquer Darman and Kudelin's domains in 1285 and suffered another counter-raid by the brothers. It was not until 1291 when a joint force of Dragutin and the Serbian King Stefan Milutin managed to defeat the brothers and, for the first time ever, the region came under the rule of a Serb, as it was annexed by Dragutin. Responding to Dragutin's annexation of Braničevo the Bulgarian prince named Shishman that came to rule the semi-independent principality of Vidin around 1280, began to attack the Serbian domains to his west.
Shishman was a vassal of Nogai Khan, Khan of the Golden Horde and sought to expand his territories to the west, invading Serbia coming as far as Hvosno, the Bulgarians failed to capture Zdrelo (near Peć) and were pursued back to Vidin by the Serbs. Milutin devastated Vidin and the rest of Shishman's dominion, making Shishman take refuge on the other side of the Danube. The two however became allies after Milutin married Serbian župan Dragoš to the daughter of Shishman, later Milutin would give his daughter Anna to Shishman's son Michael who would become the Tsar of Bulgaria in 1323.
Milutin and Nogai Khan would soon come into conflict because of the war with the Vidin principality. Nogai launched a campaign against Serbia but Milutin offered peace sending his son Stefan Dečanski to Nogai's court. Stefan stayed with his entourage there until 1296 or Nogai Khan's death in 1299.