Arnold, a continental army general was born in Norwich, Connecticut, the son of a merchant, who had married into Connecticut aristocracy but failed in business, took to strong drink, and was unable to support the family. Apprenticed to his mother's cousins, Arnold nevertheless managed to free himself to fight in the French and Indian War. He then entered business for himself.
The American Revolution tapped Arnold's capacities for leadership and gave him the fame he craved, but it also provided an outlet for his greed and selfishness. He joined in the war as head of a Connecticut MILITIA COMPANY, and upon receiving news of the Battles of Lexington and Concord, he marched the group to Boston. But not wanting to join in a siege, he participated instead in the American attempt to capture Fort Ticonderoga. It was Ethan Allen and his Green Mountain Boys, however, who took the fort, depriving Arnold of the glory a victorious command would have brought.
Arnold's next effort demonstrated his strong will and immense talent as a leader. The expedition against Canada, one part of which he led, would have taxed the abilities of any man. The main part of the drive carried his force of about a thousand men through the Maine wilderness, hampered by driving rainstorms, flooding rivers, and nearly impassable forests. They reached Quebec and joined in an unsuccessful assault on the night of December 30, 1775, under Gen. Richard Montgomery. Arnold was wounded in the battle and forced to retire.
When, in 1777, British general John Burgoyne led his forces into the New York wilderness, Arnold was with Horatio Gates, the commander of the opposing American army. Arnold did not get along with Gates, and after expressing his disapproval of the general's plans, he was ordered to the rear. He did not remain there for long but joined in the Battle of Bemis Heights on October 7, 1777. Here he performed brilliantly with the dash and recklessness that made his troops love him.
Wounded again, he was given command of Philadelphia in June 1778 after the British evacuation of the city. There his combativeness embroiled him in clashes with other commanders, and his acquisitiveness led to corruption in his command. A court-martial followed, and he was in effect cleared of most of the charges, though not all. Gen. George Washington issued a reprimand, which angered him and probably played a part in his decision to sell himself to the enemy.
Arnold, whose first wife had died, was married again, this time to nineteen-year-old Peggy Shippen of an important Philadelphia family. She took part in the conspiracy to betray West Point, where Arnold had taken command in August 1780. The plot had begun in Philadelphia the year before and was discovered in September 1780. Arnold first contacted the British in May 1779. His motives were personal, not political: he was greedy, always looking for money, and hard-pressed to keep up a style of life he could not really afford. He also resented what he took to be a lack of appreciation by Congress and the government of Pennsylvania, which questioned his administration of Philadelphia. He chose Joseph Stansbury, a Loyalist shopkeeper in Philadelphia, to convey his messages to the British general Sir Henry Clinton, who relied on Maj. John André, his adjutant general, to handle negotiations. Arnold's demands for payment varied, but in August 1780 Clinton agreed to £20,000 if Arnold's betrayal led to the capture of West Point and three thousand troops. The plot was discovered when André, carrying incriminating papers, was seized September 23, 1780, by New York militia near Tarrytown while he attempted to return from a meeting with Arnold. Arnold fled to General Clinton in New York City and an army he expected would honor his talents. He was disappointed, however, for he never received a major command. His new masters did not trust him.
After the war he lived for a short time in New Brunswick but went to England in 1791 where he died ten years later. Since 1780, Arnold's name has been synonymous in the United States with betrayal and treason.