Agia Aikaterina (Saint Catherine) is the oldest monument in Oia. The church was built sometime between 1567 and 1639 and belonged to a monastery. Agia Aikaterina once stood at the edge of the settlement of Apanomeria (as Oia was known back then) and was large enough to serve as the town’s main church. It has survived multiple volcanic eruptions and earthquakes without significant damage or alterations. The large building adjacent to the church served as the priest’s residence.