It is one of the principal buildings of the Christian city. The church was linked to the plateia by a narthex and an atrium. From the narthex, to the right, one enters the baptistery, a rectangular apsidal room containing the circular baptismal font, revetted with marble slabs. The church consists of three aisles, divided by two rows of columns surmounted by elegant capitals. The trabeation (horizontal beams or lintels which are borne up by columns or posts, as opposed to an arched construction) supported a second order of columns that opened onto the clerestories. The apse is semicircular on the inside and polygonal on the outside. The interior of the apse is occupied by the synthronon, the stepped semicircular benches for the clergy and the bishop during the liturgy. The construction of the church is dated to the first half of the 6th century AD. Other structures were added in the middle ages.