Maria and Hubertina Cassalette lived in the 17th-century castle from 1910 to 1918. Junker v.d. Maesen de Sombreff became the new master at the castle as a result of his marriage to Maria Cassalette in 1918. He lived in the castle until 1938, after which it was rented out to mining inspector W. van Waterschoot van der Gracht. In 1953, ownership of the castle passed to the manufacturer Heymeier van Heemstede, who carried out extensive restoration work on it.

Jo Eyck, the director of the paint factory of the same name, has been the owner of Schloss Wijlre since 1981. He converted the castle and park into an open-air museum for modern art. His wife is the current patron of the Sint Maternis citizens’ guild, so that the link between the castle and the guild has been preserved.

The art collection includes paintings by Limburg artists Charles Eyck, Gene Eggen, Aad de Haas, Ger Lataster und lei Molin The post-1960s are represented in Wijlre by Ad Dekkers and Peter Struycken.

Approximately 35 works by these modern artists can be seen in the park and buildings. Sculptures by the Spanish artist Munoz can be found in the inner courtyard. The castle park is also home to a bronze sculpture from 1997 by Giuseppe Penone.