This illustration is from The Lives and Times of the Popes by Chevalier Artaud de Montor, New York: The Catholic Publication Society of America, 1911. It was originally published in 1842. [Artaud de Montor (1772-1849) / https://archive.org/details/thelivesandtimes00montuoft -- Public domain -- http://commons.wikimedia.org/wiki/File:Pope Celestine IV.jpg]