In 1918 Renoir, fragile, swathed in bandages, too crippled by arthritis to hold a brush and with just a year to live, received a visit of homage from 48-year-old Matisse. The younger artist enquired about buying a painting; Renoir resp-onded with the offer of exchanging canvases. "I'm truly touched, but I can't accept," replied Matisse, then at the height of his powers. "I'm not worth it."

History has turned this verdict round. Today, Renoir, with his pulpy girls and party scenes, is a sugary crowd-puller, Matisse a father of modern art. Yet until the 1940s, Renoir's radiant, painterly painting was regarded as the unrivalled height of Impressionism, with taste-setters such as Kenneth Clark rating him above both Monet and Manet.