'New' Da Vinci's Found

On the left is Leonardo da Vinci's The Virgin and Child with Saint Anne, which is housed in the Louvre Museum in Paris. On the right is a study of a horse's head, one of three sketches discovered on the back of the painting when it was taken down to be cleaned. At first the museum staff thought these sketches were stains in the wood on which the picture had been painted, but photos taken with an infrared camera revealed three sketches. This study reminds me of a horse's head in Leonardo's Battle of Anghiari (1563) which Sir Peter Paul Rubens copied circa 1603 (CLICK). So it is in the master's style, but it has yet to be authenticated. It might be Banksy's latest trick on the art world!