Tke four-sided Byzantine structure.
Sources:
- Francesco D´Andria, The Sanctuary of St Philip in Hierapolis and the tombs of saints in Anatolian cities, in J.R. BRANDT, E. HAGELBERG, G. BIØRNSTAD, S. AHRENS, Lıfe and Death in Asia Minor in Hellenistic, Roman and Byzantine Times. Studies in Archaeology and Bioarchaeology, Oxford and Philadelphia, 2016, p. 14-16