For more than five centuries The Last Supper has been an artistic, religious and cultural icon.The art historian Kenneth Clark called it 'the keystone of European art', and for a century after its creation it was regarded as nothing less than a miraculous image. And yet there is a very human story behind this artistic 'miracle'.Ross King's Leonardo and the Last Supper is both a 'biography' of one of the most famous works of art ever painted and a record of Leonardo da Vinci's last five years in Milan.