The large historic Byzantine church of Agios Panteleimon of the 11th century is located near Bitzariano, north of Kastelli, in a location where nature is impressive. This is a three-aisled domed basilica of the Middle Byzantine period, which retains earlier architectural remnants on the south side, perhaps indicative of the fact that it has been built on the site of an early Christian church.
The fragmentary wall paintings are of particular interest and they are better preserved in the lower parts of the side walls, the central apse and the fronts of the eastern piers. The paintings are divided into three layers, dating from the 2nd half of the 11th up to the 13th century. Despite the many interventions in the temple, there is the possibility that this used to be an aisled basilica.