Arnold Cipher

In May 1779, Continental Army Major General Benedict Arnold initiated what became a series of communications with British Army Major John André, the adjutant and spy chief to Lieutenant General Sir Henry Clinton, the commander-in-chief of British forces in North America.

In these communications, which were at first mediated by Joseph Stansbury, a Philadelphia merchant, Arnold offered his services to the British.

André responded to this offer with a letter dated May 10, 1779, in which he described the types of services Arnold might provide, and described a code which they should use to obscure their communications.

[1] The book used as a key to the cipher was either Commentaries on the Laws of England by William Blackstone or Nathan Bailey's Dictionary.

/ The mass of the People are heartily tired of the War, and wish to be on / their former footing - They are promised great events from this / year's exertion—If - disappointed - you have only to persevere / and the contest will soon be at an end.

A coded communication. Handwriting by Peggy Shippen Arnold is interspersed with coded communication in Arnold's hand.