It is a typical three-aisled basilica with a narthex and exonarthex. Originally it was covered by a wooden roof.[1] Various graves have been excavated in and around the church, including three vaulted tombs and a number of box-like graves.[1] A vaulted tomb on the eastern end of the northern aisle, decorated with crosses, may be the grave of St. Achilleios.[1][2]
As the cathedral of the Metropolis of Larissa, the church was repaired in the middle Byzantine period, when it became the centre of a large cemetery stretching to the east.[2] Excavations have revealed a number of outbuildings erected during this period, probably used as storehouses, baths, charitable institutions, etc.[2] The church is attested until the middle of the 14th century,[1] and was probably demolished when the Ottomans built the Bedesten in the late 15th century.[1][2]