The Kastamonitou Monastery, officially called Konstamonitou, is an Orthodox Christian monastery in the monastic state of Mount Athos in Greece. It stands on the southeastern side of the Athos peninsula. The monastery ranks twentieth and last in the hierarchy of the Athonite monasteries.
The monastery was founded in the mid-11th century, either by an unknown member of the aristocratic Byzantine Kastamonites family, or by an unrelated person hailing from the area of Kastamon in Paphlagonia. It is dedicated to Saint Stephen. Its history during the Byzantine period is obscure, and until the 14th century it appears to have been a moderate establishment. After it was destroyed in a fire in the 1420s and restored by the Serbian magnate Radič, it attracted many monks from the South Slavic lands, and experienced a century of prosperity.
The monastery's present buildings date to the 18th and 19th centuries. The monastery has about 20 working monks. The monastery library holds 110 manuscripts and approximately 5,000 printed books.
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.