Giorgio Vasari, Lives of the Most Excellent Painters… (1850)
“ Thus becoming old, he constantly declined more and more, departing to such an extent from the excellence of his first manner, that the works he produced no longer seemed to be by his own hand: daily forgetting somewhat of his art, he descended at length to painting, not the ordinary frescoes and oil paintings of his profession only, but all sorts of things, even the meanest. ”
