For some time now the Museo del Prado has been checking the works in its collection that were consigned on deposit by the Committee for the Requisition and Protection of the Artistic Heritage - entrusted with collecting together and storing works of art belonging to private individuals and religious institutions in order to safeguard them during the Civil War - or by the Service for the Defence of the National Artistic Heritage, which was responsible for returning those works in the postwar period.

Many deposited cultural items could not be returned to their owners because they could not prove ownership, had died, were in exile, were the subject of reprisals or were simply unknown as they failed to include their names on the requisition documents. Some of these unclaimed works, principally paintings, thus remained at the Museo del Prado, the Museo de Arte Moderno and other museums in Spain.

With a different provenance, the Prado also houses 7 medals deposited in 1936 and 89 drawings assigned to the Museum in 1971 by the Directorate-General of Fine Arts.

Information regarding provenance, obtained from consulting archival documents and studying the labels and annotations on the reverse of the paintings, has made it possible to trace the circumstances of these works of art; information which the Museo del Prado is now making available to researchers and the public.