When Arnold’s treasonous plan was uncovered, her wife rejected her involvement in the plot

One of the interesting facts about Benedict Arnold and Peggy Shippen is that when Arnold’s treasonous plan was uncovered, her wife rejected her involvement in the plot. In anticipation of the British assault of West Point, General Arnold met with André on the Hudson River on September 21, 1780, and provided him documents and plans detailing the fortifications there. André was apprehended as he rode approaching British territory on Saturday, September 23, the documents were seized, and the scheme was revealed. Arnold received a note on Monday, September 25, announcing André's capture and possession of treasonous papers and maps. General George Washington had planned to visit Arnold at his residence two miles south of West Point that morning. Arnold ran upstairs to Peggy before fleeing to HMS Vulture on the Hudson River.

Shippen Peggy Arnold pretended to be hysterical in order to deceive General Washington and his staff into believing she had nothing to do with her husband's treason. Arnold may have escaped due to the delay caused by her histrionics, leaving Peggy with their young boy. She traveled to Philadelphia to remain with her family out of fear for her safety. She also pretended to be innocent when asked about her spouse, although knowing where he was. Authorities in Philadelphia quickly discovered a letter from André to Peggy written from British-occupied New York and used it to prove Arnold's wife was engaged in the treason. As a result, the Supreme Executive Council of Pennsylvania expelled her from Philadelphia. Peggy and her young son were led by her father to the Hudson River banks in November 1780, where she boarded a boat to New York City to join Arnold.