While Church was the first villain and Hale the first hero in American intelligence history, perhaps the most famous figure to emerge in intelligence from the war--and the one whose name is still associated with treason today--was Benedict Arnold. Arnold did not attend Yale University like Hale, but he did own a pharmacy and bookstore in New Haven. The same British taxes that became a rallying cry for independence by American colonists also destroyed Arnold's businesses. As a result, Arnold became a member of the Sons of Liberty.
Arnold first distinguished himself as an officer in the American militia. Arnold led forces alongside Ethan Allen in the capture of Fort Ticonderoga. George Washington rewarded Arnold's offer to lead an invasion of Canada with a commission in the Continental Army. He was seriously wounded when he was shot in the left leg during the siege of Quebec City. Washington then ordered Arnold to help organize the American forces in Rhode Island after the British successfully took Newport (see, I promised Newport would reappear--and it will again!).
Arnold's real moment came when he distinguished himself at the Battle of Saratoga, which was a defining moment of the Revolutionary War. But Arnold's left leg was again badly wounded, and he suffered from a permanent limp as a result.
Arnold's "recruitment" as a British spy began in Philadelphia. Two things happened to set events in motion. First, Arnold became involved in shady business dealings that involved war profiteering and led to his court martial. Second, he married Peggy Shippen, a young Philadelphia socialite, who had previously been romantically connected to Major John André, the head of British intelligence in North America. At some point, Arnold and André began to exchange coded letters.
André found a perfect spy in Arnold. Arnold was a high-ranking officer in the Continental Army. He had been badly wounded in combat while leading important missions, but to add insult to injury (literally), he was passed over for promotion in the Continental Army. Then, he suffered yet another insult in the form of the court martial for war profiteering. Arnold was bitter. He felt betrayed by his country, so he decided to betray it in return...
Source: National Archives 3123749