In 1643/4 the once-famous Francis Cleyn painted the unhappy young heir of Corfe Castle, John Bankes, and his tutor, Dr Maurice Williams. The painter is now almost forgotten, the painting much neglected, and the sitters themselves have left little to mark their lives, but on the table of the painting lies a book, open to an immediately identifiable and very significant page. The representation omits the author's name and the book's title; it sits there...