THE CHURCH ST. SOFIA, known as The Old Bishopric, is situated on the place supposed to be the old Centrum of the settlement. It is a three-nave basilica with a semicircular apse, a three-part nartex and an atrium (an inner yard). It is of 25,50 meter length. The central nave is separated from the two side aisles with orthogonal stone columns and brick arches. Above there is a second arcade. There are three arch windows over the apse at the East Side and a two slopes roof structure, not preserved. The apse possesses a synthronon, which can be seen today. Inside the church is plastered up and covered with frescoes.

The basilica was built at the end of 5th century and the beginning of 6th century. There were two periods in its construction, rebuilt subsequently in the beginning of the 9th century. It was an important part of the Nessebar bishop's residence.