Leonardo da Vinci was an artist, philosopher and scientist all rolled into one. But what do we really know about the handful of ethereally beautiful paintings he produced, filled as they are with hidden symbols and allegory? ‘Leonardo da Vinci: Painter at the Court of Milan’ at the National Gallery (November 9-February 5 2012) is an unprecedented gathering of what few pictures survive from the old master’s own hand (nine of fifteen, although no ‘Mona Lisa’, of course). It not only gets us closer to his understanding of beauty, but it also tells a wider story about the end of medieval values in art and society. Is it the greatest show on earth? Well, undoubtedly people will vote with their feet, so book early to avoid disappointment.