Jacob Svetoslav

Historian Plamen Pavlov theorizes that Jacob Svetoslav was a descendant of the princes (knyaze) of Kievan Rus', and estimates his birth date as being in the 1210s or 1220s.

[3] In 1261, he commanded the Bulgarian forces in a war against Hungary near Severin (western Wallachia), and in 1262 he possibly fought against Byzantium, as a Byzantine army invaded his lands in the following year during an anti-Bulgarian campaign.

[4] He also minted his own coins bearing the imperfect images of Saint Demetrius of Thessaloniki or Jacob himself, dressed as a warrior wearing a helmet and holding a sword.

[1] In 1263, the situation in Bulgaria was far from stable, as Constantine was facing both the threat of his predecessor Mitso Asen's ambitions for the throne and a large-scale Byzantine invasion.

[5] Stephen V placed him as the ruler of the Vidin province on the Danube River, previously governed for Hungary by the then-deceased Rostislav Mikhailovich, and allowed him to retain his lands to the south.

Fearing Bulgarian retribution and lack of Hungarian support should Béla IV come out victorious, in 1265 Jacob Svetoslav changed allegiance to Bulgaria and acknowledged the authority of Constantine Tih.

[8] The death of Stephen V in 1272 meant that he was succeeded by his infant son Ladislaus IV, with the widowed consort and mother of the boy, Elizabeth, as his regent.

He arrived in the capital Tarnovo to negotiate his submission with Constantine's consort Maria Palaiologina Kantakouzene, who was the dominant figure in the empire at the time due to the Tsar's paralysis.