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.