The Byzantine monuments of Santorini are scarce and this is something that is related to the high seismic activity of the island. Relics of Old Christian basilicas are preserved either in ancient temples or under Byzantine temples such as the Panagia Episkopis. Another Byzantine church is the deserted St Eirini at Perissa, St. Antonios in Imerovigli and Theotokaki in Pyrgos.
Panagia Episkopis: It lies in the outskirts of Profitis Ilias near the village Episkopi Gonias (Mesa Gonia).The church is cross shaped and it is dedicated in the Assumption. The temple was built during the 11th century AD and in its place there was another temple before, some parts of the older temple were used to build the newer temple.
Church Museum of Profitis Ilias Monastery: This monastery is situated to the southeast of Pyrgos and it is dated to the beginning of the 18th century. The monastery houses a church and folklore museum. Inside the visitor can find icons of the Cretan school (15th century) as well as church utensils of the 8th century. The folklore museum is comprised by objects of the everyday life and agricultural tools.