The Fortress of San Leo is a castle on the border of the Romagna and Marche famous as the death-place of Count Cagliostro. It contains a museum. It was one of the palaces owned by Federico da Montefeltro and his wife Battista Sforza and was a fortified, palatial retreat.Fortress of San Leo It played a large part in the 1991-film Hudson Hawk as the fictional castle of Leonardo da Vinci.