Judith Jans Leyster (also Leijster; baptised July 28, 1609 – February 10, 1660) was a Dutch Golden Age painter of genre works, portraits, and still lifes. Her work was highly regarded by her contemporaries but largely forgotten after her death. Her entire oeuvre came to be attributed to Frans Hals or to her husband, Jan Miense Molenaer. In 1893, she was rediscovered and scholars began to attribute her works correctly.
The looting of Polish cultural artifacts and industrial infrastructure during World War II was carried out by Nazi Germany and the Soviet Union simultaneously after the invasion of Poland of 1939. A significant portion of Poland's cultural heritage, estimated at half a million art objects, was plundered by the occupying powers. Catalogued pieces are still occasionally recovered elsewhere in the world and returned to Poland.
Priceless items of art still considered missing or found in other museums include works by Bernardo Bellotto, Anna Bilińska-Bohdanowicz, Józef Brandt, Lucas Cranach the Elder, Lucas Cranach the Younger, Albrecht Dürer, Anthony van Dyck, Hans Holbein the Younger, Jacob Jordaens, Frans Luycx, Jacek Malczewski, Raphael, Rembrandt van Rijn, Peter Paul Rubens, Henryk Siemiradzki, Veit Stoss, Alfred Wierusz-Kowalski, Leon Wyczółkowski, Jan Matejko, Henri Gervex, Ludwig Buchhorn, Józef Simmler, Henri-Pierre Danloux, Jan Miense Molenaer and many others.