The Washington Principles drawn up in late 1998 at the Washington Conference on Holocaust-Era Assets in Washington and signed by altogether forty-four participating nations and thirteen non-government organizations form the basis of provenance research. The Principles are a set of eleven ethical guidelines for handling issues related to artistic and cultural assets confiscated in connection with Nazi persecution and now in the holdings of public museums and collections. The respective objects are to be identified, and illegal measures carried out during the Nazi era are to be reversed. In December 1999, the German federal government, federal states and local authorities jointly passed an additional voluntary agreement—the so-called Common Statement—related to the implementation of the Washington Principles.

In response to the Washington Principles, the Coordination Office for Lost Cultural Assets in Magdeburg launched the Lost Art Internet Database. Cultural assets, particularly assets once belonging to Jews (so-called Nazi plunder), can be registered on this website as found or missing objects. The German Lost Art Foundation founded in 2015 meanwhile operates the database.

Since the passing of the Washington Principles, the municipal sculpture collection in the Liebieghaus has returned five objects to the heirs of their former Jewish owners.

The Städtische Galerie (Municipal Gallery) purchased altogether 460 objects for the Liebieghaus sculpture collection between 1933 and 1945. In keeping with the Allied restitution laws, more than 300 of those objects were returned to their rightful owners immediately after World War II—objects that had come from art collections belonging to Jews or from territories occupied by the Germans. Today the museum still holds approximately 150 artworks acquired between 1933 and 1945 whose origins have not yet been determined. Since 1945, the collection has grown by some 250 further objects. The ownership circumstances of these works during the years 1933–1945 must also be examined.

The Liebieghaus Skulpturensammlung has now set up a three-year research project to investigate the histories of these sculptures, numbering about 400 in total, to determine whether there are encumbered provenances among them—that is, whether the objects were taken from Jewish owners in connection with persecution during the Nazi era.

Anna Heckötter, the research associate in charge of the project, looks for clues pointing to each object’s previous owners. Such clues can be found in a variety of places. To start with, she examines the objects themselves in search of inscriptions, labels, stamps, seals or the like. These can already provide pointers to a gallery or auction house, an exhibition, former owners or a collection, making further research possible and necessary. With these aspects in mind, Heckötter also collects and evaluates all object-related sources on file in the museum—for example invoices, written sales negotiations, memos, photos, auction catalogues or other literature. And she thinks about which other archives might be able to provide information on the object.

Along with each artwork examined, Heckötter also documents the histories of its previous owners and their individual fates. She finds clues to the biographies of persons who once owned individual sculptures or entire collections in, for example, historical address books and residents’ registration card files, but also in photos and letters.

Another important aim of the investigative work currently being carried out at the Liebieghaus Skulpturensammlung is the documentation of the museum’s history and purchasing policies in the years 1933–1945. The provenance researcher examines the Liebieghaus’s relationships to private Jewish collectors, as well as its links to Nazi cultural policy and the art market during that period. Once the research has been concluded, the results are published.