Shortly after the Revolutionary War broke out in April of 1775, Benedict Arnold set out as captain of the Connecticut Militia Company to join the Continental Army in Massachusetts. Together with Ethan Allen and the Green Mountain Boys, Arnold captured Fort Ticonderoga in New York from the British and, later, led a grueling expedition to Quebec.

Although the subsequent battle was ultimately unsuccessful, Arnold was promoted to brigadier general. But over time, his interactions with other officers became increasingly strained and often contentious, and allegations of misconduct began to surface.

By February of 1777, Arnold began to feel slighted by Congress when several junior officers were promoted ahead of him. He received a promotion to major general in May, but was denied the seniority he felt he deserved, and, in July, he submitted his resignation. Convinced by George Washington to reconsider, Arnold once again joined the Continental forces, where he proved instrumental in thwarting the British siege of Fort Schuyler and later displayed considerable bravery in charging the British in the Battle of Saratoga—resulting in General Burgoyne’s surrender days later.

In May of 1778, Arnold was appointed military governor of Philadelphia, where he began socializing with many Loyalists and maintaining an extravagant lifestyle well beyond his means. He was soon accused of using his military office for personal gain and was faced with misconduct charges and a court-martial. Laden with debt, embittered by Congress’s refusal to reimburse him for war expenses paid out of pocket and angered by what he believed to be ingratitude for his service to the country, Arnold began negotiating with British officers to defect.

On September 21, 1780, Arnold struck a deal with Major John Andre to hand over the American fort at West Point in exchange for £20,000 and a command in the British army. Unfortunately for Arnold, Major Andre was intercepted days later with letters revealing his involvement and the treasonous plot was foiled. Shortly after Arnold’s desertion, Sergeant Major John Champe embarked on an elaborate double-agent spy mission to bring him to justice, but the plan was stymied at the last minute and Arnold escaped.

Benedict Arnold died in London in 1801—despised by his former countrymen and erased from Revolutionary War monuments—but his name lives in infamy in American history, synonymous with the word “traitor.”