Ivan Asen
The teenager Ivan Asen had a strong claim to succeed his uncle, but Kaloyan's Cuman widow married Borilthe son of one of Kaloyan's sisterswho was proclaimed emperor. The exact circumstances of Boril's ascension to the throne are unknown. The 13th-century historian, George Akropolites, recorded that Ivan Asen soon fled from Bulgaria and settled in the "lands of the Russians" (in the Principality of Halych or Kiev). According to a later source, Ephrem the Monk, Ivan Asen and his brother, Alexander, were taken to the Cumans by their tutor before they moved to the Rus' principalities. Florin Curta and John V. A. Fine write that a group of boyars had tried to secure the throne to Ivan Asen after Kaloyan's death, but they were overcome by Boril's supporters, and Ivan Asen had to leave Bulgaria. Historian Alexandru Madgearu proposes that primarily boyars who opposed the Cumans' growing influence had supported Ivan Asen.