Virgin and Child with the Infant Saint John the Baptist

In his life of Leonardo da Vinci, the 16th-century biographer Giorgio Vasari singled out a Madonna that had belonged to Pope Clement VII. What amazed him was a small detail, a carafe of water holding a few flowers, its droplets painted so well they seemed more alive than life itself. Look to the left of the Virgin here. A clear glass vase of flowers stands on the ledge, and scholars have linked this round panel with the picture Vasari described. For a long time it passed as Leonardo's own work. Today it is recognised as Lorenzo di Credi's, painted in Florence in the 1490s, and his hand shows in the crisp, exact drawing of every curl and fold. On the other side lies an open book where you can read Isaiah's prophecy that a virgin will conceive and bear a son called Emmanuel.