Virgin of the Rocks
It has always been agreed that the Louvre "Virgin of the Rocks" is entirely by the hand of Leonardo da Vinci. The "Virgin of the Rocks" in London has generally been seen as having been designed by Leonardo and executed with the assistants. The Louvre website and various authors suggest that the entire painting is by Ambrogio de' Predis, painted under Leonardo's supervision between 1485–1508, or perhaps largely the work of de Predis, with minor intervention by Leonardo.