Rembrandt van Rijn, "the Braunschweig terrier", around 1637, Herzog Anton Ulrich Museum in Braunschweig. 

The Herzog Anton Ulrich Museum in Braunschweig discovered a chalk drawing of a dog has been identified as a work by Dutch master Rembrandt van Rijn. Known as "the Braunschweig terrier," the image is believed to date from around 1637; it has been in the museum's collection since 1770.