Kaliman Asen I, also known as Coloman Asen I or Koloman (Bulgarian: Калиман Асен I; 1234-August/September 1246) was Emperor (Tsar) of Bulgaria from 1241...

Kaliman Asen II (Bulgarian: Калиман Асен II), or commonly, but less accurately Koloman Asen II, ruled as tsar of Bulgaria for a short time in 1256. The...

Bulgaria converted to Christianity in the ninth century, the ruler Boris I (852–889) was using the Slavic title knyaz (prince). For much of its later...