Fra Filippo Lippi (c. 1406 1469) was an orphan brought up in a convent, who was persuaded by his elders to take vows. He then caused a scandal by running off with a nun. Happily, the Medici family had always observed his talent and bent their powerful muscles to get the couple laicised. Their child, Filippino Lippi (1457-1504), also became a highly successful painter. Filippo's majestic frescoes in the cathedrals of Spoleto and Prato gave him the opportunity to paint crowd scenes. His Madonnas and saints are holy, serene and unworldly, but his crowds are common clay, men, women and children as he saw them. Moreover, they became more and more realistic, as a comparison of three works in the London National Gallery shows. The first two, lunettes, painted for the walls of the Medici family palace in Florence, an Annunciation and a group of Seven Saints, are charming and decorative and lively, and in admirable perspective. The third, The Trinity and Four Saints, is part of an altarpiece made for a community chapel in Pistoia ten years later. It is incomparably the best of the three. In realism and authority, in dignity and grace, it is a huge advance. The explanation is that the first two were executed entirely in tempera, used in the traditional way, while the third was painted in egg tempera with oil as the vehicle. That explains the precision, depth, fluidity and sheer bravura of this grand work.