Margaret "Peggy" Shippen Arnold

Margaret Shippen was born in Philadelphia in 1760 into one of the city's most prominent and socially connected families. Her father, Edward Shippen, was a prominent judge who attempted throughout the Revolution to maintain the family's position by carefully avoiding conspicuous commitment to either side. During the British occupation of Philadelphia in 1777–1778, young Peggy Shippen was among the most celebrated beauties of the occupying army's social season, forming close friendships with several British officers including the flamboyant Major John André, who sketched her portrait and appears to have maintained a correspondence with her even after the British withdrew.

In April 1779 she married General Benedict Arnold, then the American military commander of Philadelphia and a figure of legendary battlefield valor whose ego and financial recklessness had made him numerous enemies within the Patriot establishment. The marriage brought together a socially ambitious young woman with British connections and a resentful, debt-ridden general who felt inadequately rewarded for his sacrifices. By 1780 Arnold was secretly corresponding with British officials through an intermediary — John André, Peggy's former social companion — and negotiating to hand over the American fortress at West Point in exchange for money and a British commission. The precise extent of Peggy's involvement in initiating or sustaining the conspiracy remains contested among historians, though some evidence suggests she served as a go-between and was more deeply involved than she let on after the plot was exposed.

When the conspiracy unraveled in September 1780 after André's capture and Arnold's flight to British lines, Peggy performed a scene of apparent madness and hysteria so convincing that Washington and his officers believed her innocent and escorted her out of the American lines. She later joined Arnold in British-occupied New York and eventually in London and Canada. Scholars re-examining her correspondence and behavior have concluded that she likely knew the full extent of the plan, making her one of the Revolution's most skillful and consequential female actors — though her role was played in service of the British crown rather than American independence.