“By general agreement, he was the best artist of the twentieth century. How good was that? His sheer significance, as the god of modernity in painting, has always beggared ultimate judgment. Now the issue is being forced, at the Prado and the Reina Sofía, by direct comparisons of his work with that of the Old Masters who, from time to time, were important to him, either as models or as goads—notably Velázquez and Goya.”