A previously unrecorded painting attributed to Giovanni Francesco Barbieri, the Italian Old Master known as il Guercino (1591-1666), has been consigned to Cambridge auction house Cheffins.
It will be offered in its sale on March 7-8 with an estimate of £80,000-120,000.
The 22in x 2ft 6in (56 x 76cm) oil on canvas depicts an Italian mastiff in a mountainous landscape. While dogs feature in other Guercino paintings, the only other known canine portrait is Portrait of the Aldrovandi Dog which sold at auction in the 1970s and is now in the Norton Simon Museum in Pasadena, California.