Tracing the Activity of Ancient Architects and Craftsmen between Hierapolis of Phrygia and Aphrodisias. The Case of the Upper Portico in the Sanctuary of Apollo in Hierapolis

The poliadic Sanctuary of Apollo is situated in the centre of Hierapolis of Phrygia and has been the object of extensive excavations and architectural studies during the last twenty years. The project of the sacred area was elaborated in the Augustan period and the building activities lasted at least for a century. A group of blocks pertaining to a dismantled Corinthian portico was stored in the sanctuary after the extensive demolitions carried out in proto-Byzantine period. The study of these blocks, so far attributed to various buildings, allowed to formulate a hypothetical reconstruction of the elevation and layout of the portico: a colonnade 6.41 m high, distinguished by Corinthian capitals, fluted friezes and cornices with modillions, stood around the upper terrace of the sanctuary, where the excavations unearthed scarce remains of the portico’s foundations. The monument was provided in the intercolumniations with wooden pinakes which delimited specific spaces for rituals and processions. The portico was also characterised by a sector with protruding aediculae, perhaps a propylon on the model of that of the Sebasteion in Aphrodisias. The analysis of the architectural decoration indicates a date in the late Flavian period, thanks to comparisons with Ephesian monuments such as the Fountain on the south side of the Upper Agora and the Domitianbrunnen and with the Zeus Temple of Aizanoi. Furthermore, an extraordinary comparison, for the exact sequence of mouldings of the entablature, can be found in Aphrodisias in the second order of the South Hall of the Civil Basilica, giving us the opportunity to investigate the relationship between the architectures of these urban centres. It is likely that one architect was involved in both the architectural projects: he could have taken advantage of the same design used in a secondary part of the huge Aphrodisian Basilica for a new autonomous portico in Hierapolis. On the other hand, the stylistic differences between the monuments suggest that two distinct artistic workshops were involved in the building sites.