Arnold, who was raised in a respected family in Norwich, Connecticut, apprenticed with an apothecary and was a member of the militia during the French and Indian War (1754-1763). He later became a successful trader and joined the Continental Army when the Revolutionary War broke out between Great Britain and its 13 American colonies in 1775.
During the war, Arnold proved himself to be a brave, skilled leader, helping Ethan Allen’s troops capture Fort Ticonderoga in 1775 and then taking part in the unsuccessful attack on British Quebec later that year, which earned him a promotion to brigadier general. Arnold distinguished himself in campaigns at Lake Champlain, Ridgefield and Saratoga, and gained the support of George Washington. However, Arnold had enemies within the military and in 1777, a group of lower-ranking men were promoted ahead of him. Over the next several years, Arnold married a second time and he and his wife led a lavish lifestyle in Philadelphia, racking up substantial debt. Money problems and the resentment Arnold felt over not being promoted faster were factors in his decision to become a turncoat.
In 1780, Arnold was given command of West Point, the American fort on the Hudson River in New York (and future home of the United States Military Academy, established in 1802). Arnold contacted Sir Henry Clinton, head of the British forces, and proposed handing over West Point and its men. On September 21 of that year, Arnold met with British Major John Andre and made his traitorous pact, in which the American was to receive a large sum of money and a high position in the British army. However, the conspiracy was uncovered and Andre was captured and killed. Arnold fled to the enemy side and went on to lead British troops in Virginia and Connecticut. He later moved to England, though he never received all of what he’d been promised by the British. The former American hero and patriot died in London, in relative obscurity, on June 14, 1801.