The Church of the Dormition of the Theotokos
The Dormition of the Theotokos is located in Stagoi (modern Kalambaka), which was a stronghold and bishopric in Thessaly starting perhaps the 10th century. It is a three-aisled basilica, constructed probably in the late 11th or early 12th century on the foundations of a church from the 4th-6th century. The ambo, chancel screen, and synthronon of the earlier structure survive in the interior, and there are mosaics under the pavement of the floor. Some late 12th century frescoes (standing portraits of saints) remain in the south aisle, although most of the decoration is from the latter part of the 16th century.
Oxford Dictionary of Byzantium