Boril of Bulgaria

Boril Борил
Golden seal of Boril
Tsar of Bulgaria
Reign	1207–1218
Predecessor	Kaloyan
Successor	Ivan Asen II
Spouse	Cuman princess
House	Asen dynasty

Boril (Bulgarian: Борил) was emperor (tsar) of Bulgaria from 1207 to 1218. He was the son of an unnamed sister of his predecessor, Kaloyan. After Kaloyan died unexpectedly in October 1207, Boril married his widow, a Cuman princess, to seize the throne. His cousin, Ivan Asen fled from Bulgaria, enabling Boril to strengthen his position. His other kinsmen, Strez and Alexius Slav, also refused to acknowledge him as the lawful monarch. Strez took possession of the land between the rivers Struma and Vardar with the support of Stefan Nemanjić of Serbia. Alexius Slav secured his rule in the Rhodope Mountains with the assistance of Henry, the Latin Emperor of Constantinople.

Boril launched unsuccessful military campaigns against the Latin Empire and the Kingdom of Thessalonica during the first years of his reign. He convoked the synod of the Bulgarian Church in early 1211. At the assembly, the bishops condemned the Bogomils for heresy. After an uprising broke out against him in Vidin between 1211 and 1214, he sought assistance from Andrew II of Hungary who sent reinforcements to suppress the riot. He made peace with the Latin Empire in late 1213 or early 1214. After Henry died in 1216 and Andrew II left Hungary for a crusade, Ivan Asen returned to Bulgaria. He defeated Boril who was captured and blinded in Tarnovo in 1218.