Agios Ioannis Prodromos (St. John the Baptist), at the edge of Kastania, is a small compact domed cross-in-square church with cross arms of uneven width. The dome is cylindrical and the apse three-sided. It belongs to a variation of the cross-in-quare type that is rare in the byzantine period, being one of its earliest examples. The church is very well built. It features cloisonné masonry, with elaborate brick decoration and immured ceramic plates, with only their sockets still preserved. The wall paintings belong to a single phase and date to the mid- 13th century. According to a foundation inscription, the church was built and decorated with funds raised by the entire village, both the rulers and the common people.