In the opening years of the sixteenth century the art of painting had attained such a pitch of excellence that unless carried onward by a supreme genius it could hardly hope to escape from the common lot of all things in nature, and begin to decline. After Botticelli and Leonardo, the works of Andrea del Sarto, "the perfect painter" as he has been called, fall rather flat; and no less a prodigy than Michelangelo was capable of excelling his marvellous predecessors, or than Raphael of rivalling them.