The largest church in the city was a three-aisled basilica with an entry hall (Narthex) at the west end, a pulpit in the centre and an apse with seating steps (Synthronon) for the clergy in the east. The chancel in front of it was separated by a screen, and the apse was set into the main structure of the Roman baths. The basilica has a skewed plan, and most of it was built of stone reused from older buildings. The surviving west staircase of the ambo and the ornamental chancel-screen are early Byzantine works.
Building phases: I Basilica with columns and a wide narthex (5-6th century AD); II Extension of the west end of the nave and aisles. An arcade was built above the columns. III Supporting pillars were inserted between the columns. The church was abandoned around 1300.