Mega Spilaio is a Greek Orthodox monastery in the municipality of Kalavryta, in the Peloponnese peninsula in southern Greece.
The monastery is located in a large cave in a sheer cliff, where the western slopes of Mount Chelmos drop down to the gorge of the Vouraikos river. The cave was known in antiquity, and the geographer Pausanias reports that the daughters of Proetus found refuge there during their madness. In the first Christian centuries, Christian hermits occupied the cave.
According to tradition, the monastery is one of the oldest in Greece, reputedly founded in 362 by the Thessalonian brothers Symeon and Theodore, who with the help of Euphrosyne (a local shepherdess, honoured as saint for her part in these events) discovered in the cave the icon of the Theotokos painted by Luke the Evangelist.
Its medieval history under Byzantine and Latin rule is obscure. The monastery gained prominence only from about 1354, when it served as the residence of the Orthodox Metropolitan of Patras, since the city was still occupied by the Latins and the seat of a Latin archbishopric. The complex suffered large-scale destructions in 849, 1400, and 1640, when it was comprehensively rebuilt.
Several of the monks became members of the Filiki Etaireia and took part in the Greek War of Independence. In 1934, the katholikon was destroyed in a fire, and replaced by a new church in 1937. On 8 December 1943, the German 117th Jäger Division destroyed the monastery and executed 22 monks and visitors as part of reprisals that culminated a few days later with the Massacre of Kalavryta.
The monastery was rebuilt from the ground after the war, and now comprises an eight-storey complex set in the 120 metres high cliff face.
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.