For most, the name Benedict Arnold is synonymous with treason. It’s also associated with West Point, but although West Point is the site of Arnold’s (attempted) exchange of the fort for cash, the story actually began in Philadelphia.
During the winter of 1777-78, while the continental army was freezing and starving at Valley Forge, the British Army was living it up in Philadelphia. Parties and balls were a regular occurrence and were regularly attended by the local ladies (it was a great place for husband hunting – if you were in the market for a British officer). One of the regular attendees was Peggy Shippen, from a very wealthy, long established, politically connected family – and considered one of the prettiest girls in Philadelphia. Peggy’s family home is no longer standing, but you can still see the home of her uncle, Dr. William Shippen (who became Director of Hospitals for the Continental Army).
Peggy’s family walked a fine line during the Revolution, trying to stay neutral during the war (it worked for her father Edward – he retained his property during the British occupation, and still became Chief Justice of the Pennsylvania Supreme Court after the revolution).
One of the men Peggy partied with was British Major John Andre, the man in charge of many of the festivities, who would become British General Clinton’s spy chief (Andre lived in Ben Franklin’s house during the occupation of Philadelphia (Ben Franklin’s Ghost House).
After the British left Philadelphia to return to New York, Peggy continued to correspond with her “dear friend” Andre. During the summer of 1778, Peggy met Benedict Arnold, who was then Continental military commander of Philadelphia and living in the Master’s/Penn House. Despite a 20 year difference in their ages (Peggy was 18), they married on April 8, 1779 and she moved in with Arnold. This house, which had been home to British General William Howe during the occupation of Philadelphia, later become the Executive mansion lived in by Presidents Washington & Adams. Today, the site is part of Independence National Park and is interpreted with information about slavery during Washington’s presidency (The Footprints of a Runaway Slave – George Washington & Slavery in Philadelphia).
During this time, Arnold bought the Mount Pleasant estate for his new bride. This gorgeous Georgian home in Fairmount Park (built 1760-61) is now managed by the Philadelphia Museum of Art and furnished with period pieces from the collection (although as of 11/18 it is closed for renovations). The Arnolds moved to West Point soon after the purchase and never lived in the house. After the treason conviction, it was seized by the government and later leased to Baron von Stueben. Disillusioned by his treatment by Congress and needing cash (he was extravagant and Peggy was high maintenance), Arnold was ripe for treason. It’s now generally agreed that it was Peggy who established the connection between Arnold and Andre. She definitely acted as intermediary – her letters to Andre contain invisible ink messages from Arnold and British documents from 1792 record that Peggy received £350 for handling secret dispatches. By the summer of 1779, Arnold was providing information to the British about troop movements. In August of 1780, he obtained command of West Point and actively began working to weaken its defenses to make it easy for the British to capture the fort. After a rendezvous with Arnold, Andre was captured (and later hanged) and the plot exposed. Arnold fled to New York, leaving Peggy behind. She was apparently a great actress, as her hysterical performance convinced Washington and Alexander Hamilton of her innocence. She was allowed to return to Philadelphia, although forced out soon after when her role in the plot was revealed – later joining her husband in New York (where he became an officer in the British Army). After the war, they moved to London, where both died.