Bulgarian–Serbian Wars (medieval) in the context of Bulgar–Serb War (839–842)

Vlastimir (Serbian Cyrillic: Властимир, Greek: Βλαστίμηρος; c. 805 – 851) was the prince of Serbia from c. 830 until c. 851. Little is known of his reign. He held Serbia during the growing threat posed by the neighbouring, hitherto peaceful, First Bulgarian Empire, which had expanded significantly toward Serbia.

At the time, the Bulgarian Empire and the Byzantine Empire were at peace by treaty, and although the Byzantine Emperor was overlord of the Serb lands, he was unable to aid the Serbs in a potential war. Presian I of Bulgaria eventually invaded Serbia, resulting in a three-year-war, in which the Bulgarian army was devastated and driven out. Vlastimir then turned to the west, expanding well into the hinterland of Dalmatia. He is the eponymous founder of the Vlastimirović dynasty, the first Serbian dynasty.

Krajina Belojević (Serbian: Крајина, Greek: Κράινα), was the 9th century local Slavic chieftain from the region surrounding Trebinje, who ruled the area with a title of župan. The same region centered on Trebinje, also known as Travunia, was earlier ruled by Krajina's father, the local lord Beloje. At the time of Krajina's rule, the region was still under suzerainty of the Principality of Serbia, and he was in vassal relation to its ruling Vlastimirović's. In 847/848, after the Bulgarian–Serbian War (839–842), victorious Prince Vlastimir of Serbia (r. ca. 836-850) married his unnamed daughter to Krajina, thus elevating his and his province rank. In doing so his father-in-law, eponymous founder of the Vlastimirović's, dynasty which rule Serbia until 969, granted them independence. Although Krajina's father sought to free himself and his province from Serbian suzerainty, and though Krajina succeeded in achieving that goal through marriage with Vlastimir's daughter, he continued to serve in office as župan under Mutimir (r. 850–891). With the Vlastimir's daughter Krajina had a son that would succeed him, Hvalimir (Greek: Φαλιμἑρης). Hvalimir in turn had a son, Čučimir (Greek: Τζουτζημέρης; r. first half of 10th century), who was the last known Belojević in charge of Travunia before it was annexed by the Byzantines.