After the war, thousands of works of art that had fallen into enemy hands were found in Germany and brought back to the Netherlands. Some of those works are still in the custody of the Dutch State. This collection is known as the NK collection (‘Netherlands Art Property collection’). Between 1998 and 2005, the provenance of the roughly 5000 objects that were in the collection at the time was investigated by Bureau Herkomst Gezocht (‘Origins Unknown Agency’). The data were published on the website ‘Herkomst Gezocht‘.
Thousands of works of art were never recovered by the authorities. Information on some of these works was published on the website in 2016.
Since 1 September 2018, the ‘Herkomst Gezocht’ website has been maintained by NIOD’s Expert Centre Restitution.