It was Baudelaire, I believe, who was the first to denounce the terms “avant-garde” and “revolutionary” as applied to the arts. They belonged to the world of politics and the military, and ought to stay there. It was only in the nineteenth century that they became current in the world of the arts, and in the twentieth that they became clichés. What they were attempting to describe had always been part of the process of history—and fashion: as long ago as Dante, the poet mentions the painter Cimabue as having recently been all the rage, but now “Giotto has the cry” (“ed ora ha Giotto il grido”). He speaks of this as no surprising thing, only a symptom of the endless revolution in human affairs and tastes. The history of art, and of painting in particular, is crammed with examples. Piero della Francesca, that monument of quattrocento classical purity, was old-fashioned as early as 1510 or so, when a roomful of his paintings was demolished to make way for the new wonder, Raphael. (How many of us would now rather have the Pieros, instead of the frescoes of the dizzily accomplished, divinely boring Raphael?)

It was in mid-career that Rembrandt sank out of fashion, and into bankruptcy. He was no longer interested in the startling, trompe l’oeil brilliance of his earlier portraits, and would-be patrons were not interested in what he now wanted to do. After his death, a major pundit of the day remarked of his work