The Holtfeld Castle was first mentioned in a feudal register from Osnabrück in 1380; the Lords of Todrank, who resided in Ravensberg Castle, were considered the owners. In 1497, this lineage died out, and through the last heiress, the castle passed to the Imperial Barons of Wendt, who inhabited it until 1863.
During this time, the manor house in Renaissance style was built from 1599 to 1602. The inner gatehouse was erected in 1632, and the outer one in 1705. In the early 18th century, the layout of the estate was redesigned.
Gatehouse of Holtfeld Castle In 1863, the Counts of Marchant d'Ansembourg inherited the castle and 600 acres of land. The counts passed the castle to a collateral line, which sold it to the Counts of Galen. However, they lacked the means to maintain the castle and leased it out. In 1936, the Counts of Korff-Schmising zu Tatenhausen purchased the building.
In the 1930s, the building was heavily deteriorated and uninhabitable. After the renovation in 1936, the agricultural school moved in. In 1945, the writer Hans Roselieb took his own life here. After being used as a sanatorium, the castle operated as a hotel until 1977. Then, apartments were created in the outbuildings, and today the castle serves as an office, exhibition space, and residence.
The single-wing main building has two decorative gables with volutes and a square corner tower. The main stone elements are plastered. The windows are one to three-part. The inner gatehouse was built in 1632; the portal is rounded and framed with blocks. The outer gatehouse is from 1705, and the portal is adorned with a segmental arch and bears a coat of arms. The economic buildings of the complex are timber-framed structures from 1660. The two-bay vaulted castle chapel is located in the main building.
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.