Constantine Tikh of Bulgaria

Konstantin Tih Константин Тих Асен
Tsar of Bulgaria
Portrait of Konstantin Asen of the frescoes in the Boyana Church
Reign	1257–1277
Predecessor	Mitso Asen
Successor	Ivaylo
Spouse	Irene Doukaina Laskarina Maria Palaiologina
Issue	Michael
House	Asen dynasty
Father	Tihomir (Tih)

Konstantin Tih (Bulgarian: Константин Тих Асен; fl. 1257–77) or Constantine I (Константин I), was the emperor (tsar) of Bulgaria from 1257 to 1277.

Konstantin Tih was a wealthy Bulgarian boyar (or nobleman) whose estates were located in the region of Sofia or Skopje. Konstantin stated in his charter to the Saint George Monastery near Skopje that Stefan Nemanja of Serbia was his grandfather. The Byzantine historian, George Pachymeres, described him as a "half-Serbian". He could have been related to the Serbian royal house through either his mother or father. If he was a patrilinear relative of Nemanja, his father, Tih, may have been the son of Nemanja's brother, Tihomir, according to historian Srdjan Pirivatrić. Pirivatrić and other scholars also say, Konstantin may have been a son or a nephew of the boyar John Tihomir, who controlled Skopje in the late 12th century. If Konstantin was related to the Serbian royal house through his mother, a daughter or a niece of Nemanja must have been his mother.

Konstantin Tich mounted the Bulgarian throne after the death of Michael II Asen, but the circumstances of his ascension are obscure. Michael Asen was murdered by his cousin, Kaliman in late 1256 or early 1257. Before long, Kaliman was also killed, and the male line of the Asen dynasty died out.

Rostislav Mikhailovich, Duke of Macsó (who was Michael and Kaliman's father-in-law), and the boyar Mitso (who was Michael's brother-in-law), laid claim to Bulgaria. Rostislav captured Vidin, Mitso held sway over southeastern Bulgaria, but none of them could secure the support of the boyars who controlled Tarnovo. The latter offered the throne Konstantin who accepted the election.