Sebastokrator Alexander Asen

Sebastokrator Alexander Asen was the second son of the Bulgarian tsar Ivan Asen I and Tsarina Elena. After Tsar Kaloyan's murder in 1207, he and his brother Ivan Asen II fled to the Cumans and later to the southern Russian lands. They did so under threat of death from the usurper Boril. In 1217 he returned from exile.

With the support of Russian mercenaries in 1218, Alexander helped overthrow Boril and proclaim Ivan Asen II the next Bulgarian tsar. After Boril's overthrow, Alexander received the dignity of sebastokrator, and Sofia and its region were granted to him as an appanage.

In 1232, with the help of Russian mercenaries, Alexander managed to prevent a Hungarian attack on the Belgrade region. In 1233, a Bulgarian army led by Sebastokrator Alexander confronted the Hungarians and defeated them near Vidin, in Oltenia and near Braničevo, restoring Bulgarian possession of the occupied regions.

Alexander had a son named Kaliman (Coloman), who took the Bulgarian throne as Kaliman II Asen after Michael II Asen's murder in 1256, but was deposed and killed after a few months.