Mentioned in De Administrando Imperio (DAI) of Byzantine Emperor Constantine VII (r. 945–959), Beloje was a contemporary of Serbian ruler Vlastimir (r. 836–851).
[1] Vlastimir married his daughter to Beloje's son Krajina, and "desiring to ennoble his son-in-law",[2] elevated his rank to archon (prince) and made him independent.
[3] T. Živković theorized that Beloje sought to free himself of Serbian rule, and that Vlastimir prevented this through a political marriage between the two families, possibly prior to the Bulgar–Serb War (839–842).
[5] There is a hypothesis that the legendary king Pavlimir Belo (or Belimir) mentioned in the Chronicle of the Priest of Duklja (CPD) was supposedly based on Beloje.
[9] The CPD mentions this individual, Belo, as being born as Pavlimir, receiving his nickname from his relatives and other Romans from bello, "because he very much loved war".