Mount Fokas is a 862m high hill in in the area of Corinth. A medieval settlement existed on its trapezoid summit and later a castle was built by the Franks in the 13th century (or perhaps by the Byzantines, a little earlier).
The castle controlled the plains of Nemea and the main route to the center of Peloponnese. It had visual contact with other Frankish castles in the area like Acrocorinth or Agios Vasilios but also with some castles in Central Greece, on the opposite side of the gulf of Corinth.
Only a few ruins of the walls and from the settlement remain at the lower part of the rock.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.