Distinguished American combat officer Benedict Arnold met a British commander in secret with a plot to trade the colonial stronghold at West Point for cash on this day in history, Sept. 21, 1780. 

The meeting with British Major John Andre took place at the Hudson River home of New York loyalist Joshua Hett Smith. 

General George Washington soon discovered the treachery. 

Arnold escaped to British-controlled New York City and served in the losing army for the remainder of the American Revolution, which ended in October 1781. 

He died in London in 1801. Andre was captured and executed. 

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The name Benedict Arnold remains a synonym in American English for "traitor" nearly 250 years later. 

"Historians have several theories about why Arnold became a traitor: greed; mounting debt; resentment of other officers; a hatred of the Continental Congress; and a desire for the colonies to remain under British rule," writes the National Constitution Center, noting that the Sept. 21 Arnold-Andre meeting "was a disaster for both men."

Arnold was reportedly offered 20,000 British pounds to hand over the American fortification on the Hudson River, now the home of the U.S. Military Academy. 

A successful Connecticut merchant before the war, he reportedly coveted wealth above patriotism. 

"One officer presciently stated that 'Money is this man's God, and to get enough of it he would sacrifice his country,'" writes History.com.

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Yet Arnold had served the cause of independence with great distinction from the earliest days of the American Revolution — and rose to the rank of major general. 

He joined the army of New England Minutemen in their 11 month-long siege of Boston in April 1775, immediately following the battles of Lexington and Concord. 

He then helped Ethan Allen and the Green Mountain Boys capture the British garrison at Fort Ticonderoga on Lake Champlain in May. 

The cannons from Ticonderoga, in one of the more heroic feats of logistics in American history, were dragged by ox train to Boston the following winter and mounted on Dorchester Heights. 

The show of firepower over the city forced the British to flee Boston in March 1776, liberating the city after years of conflict with the crown four months before the Declaration of Independence. 

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Arnold was wounded in the ill-fated Battle of Quebec on New Year's Eve 1775/76, then wounded again, this time badly, helping lead rebel forces during the Battle of Saratoga in 1777. 

The stunning colonial victory at Saratoga encouraged France to join the American cause. 

Washington trusted Arnold enough to give him command of West Point, a fortress critical to control of the Hudson River, which divided New England from the rest of the colonies.

"Washington thought of Arnold as his ‘fighting general,' and supported him as much as he could up to the time of Benedict Arnold’s defection," biographer James Kirby Martin told the library of George Washington's Mount Vernon. 

His heroism on the battlefield made his treachery all the more appalling. 

"Despite his military successes, Arnold felt he did not receive the recognition he deserved. Indeed, many of his fellow officers reportedly found General Arnold to be vain, emotional and greedy," reports History.com. 

"He resigned from the Continental Army in 1777 after Congress promoted five junior officers above him. General George Washington … urged Arnold to reconsider."

Arnold's first wife, Margaret Mansfield, died in Connecticut in June 1775, while the soldier was already serving the colonial war effort. 

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He married American loyalist Margaret Shippen, a British spy, in Philadelphia in 1779. 

She was a friend and reported love interest of Major Andre and helped facilitate their plot. 

Arnold reportedly received only 5,000 of the promised 20,000 pounds for his treason. 

Benjamin Franklin discussed the betrayal in a letter sent to hero of two revolutions Marquis de Lafayette in 1781, reports the National Constitution Center. 

"Franklin compared Arnold to Judas and said it was ‘a miserable bargain, especially when one considers the quantity of infamy he has acquired to himself and entailed on his family," the center writes.