In 1009 Herswithehusen (Hardehausen) became the property of Meinwerk, bishop of Paderborn. The abbey was founded in 1140 by bishop Bernhard I of Paderborn as a daughter house of Kamp Abbey on the Lower Rhine. Construction was completed with the dedication of the church in 1165.
During the Thirty Years' War the abbey was looted and destroyed. During its reconstruction in the years 1680 to 1750 it received its present form.
In 1803 the abbey was secularised, and the monks expelled. The contents were sold or auctioned, and the church was demolished in 1812. The estates were rented out as state property.
Hardehausen was briefly re-founded as a Cistercian monastery in 1927, but the new community was brought to an end by an order of dissolution issued by the National Socialist government in 1938, when the buildings and grounds were sold to the Henschel company from Kassel, from whom they were acquired by the Verein für katholische Arbeiterkolonien ('Union for Catholic Workers' Colonies'). In 1944 the Nationalpolitische Erziehungsanstalt (Napola) Bensberg transferred to Hardehausen. At this period an external work party from Buchenwald concentration camp, consisting of 30 prisoners, were deployed for forced labour in Hardehausen.
Since 1945 the former monastery has been used for the educational activities of the present Archdiocese of Paderborn. In 1970 all the buildings on the site were altered and extended for their educational functions.
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.