Kasteel Radboud is one of a number of castles in North Holland, the building was commissioned by Floris V. The exact date of building is not known but the castle was completed before the St. Lucia's Flood of 13 December 1287. On 24 June 1517 the castle saved some of the Medemblik townsfolk from the raids of Grutte Pier and his Arumer Zwarte Hoop (band of marauding pirates).
On 12 August 1588 the castle surrendered to Diederik Sonoy and the Geuzen. The defensive function of the castle was reduced with the building of walls around the city of Medemblik in 1572 and due to both dismantling and lack of maintenance there was attrition of the castle buildings.
In 1889 the control of the property was returned to the state. Restorations were done by the State architect J. van Lokhorst with advice from R.J.H. Cuypers and the castle was used for the district court of justice until 1934. In 1931 a cannery near the castle burnt down exposing the foundations of a tower on the north west of the site and during 1936 the castle-moat was dug again.
From 1964 to 1965 further restorations were done with a more historical and architectural correctness and some of the previous renovations were removed.
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.