Treasonous letter from Benedict Arnold — Image of a coded letter: Peggy Shippen Arnold's handwriting is interspersed with coded writing in Benedict Arnold's hand; Arnold's writing would have been in invisible ink
Photo Credit: By Benedict Arnold; Peggy Shippen Arnold - From the digital collections of the New York Public Library.- Public Domain, https://commons.wikimedia.org/w/index.php?curid=5747344