From the diary of Samuel Pepys (1663-1703)
... but took coach and called at Faythornes to buy some prints for my wife to draw by this winter; and here did see my Lady Castlemaynes picture, done by him from Lillys, in red chalke and other colours, by which he hath cut it in copper to be printed. The picture in chalke is the finest thing I ever saw in my life I think, and did desire to buy it; but he says he must keep it awhile to correct his Copper plate by, and when that is done, he will sell it me. -- Pepys' Diary, 7 Nov. 1666