Benedict Arnold, V (January 14, 1741–June 14, 1801) was a Continental Army and British military leader. As a general in the Continental Army during the American Revolutionary War, Arnold became well known for leading successful campaigns and winning battles. Later during the Revolution he plotted with the British army to arrange for Washington's kidnapping at West Point but when the plot was thwarted Arnold left the Continental forces and joined the British.

Born in Norwich, Connecticut, Arnold was appointed a colonel in the Massachusetts's militia in 1775. He and Ethan Allen captured Fort Ticonderoga, gaining needed supplies and cannons that were later used in the Siege of Boston. In 1775 Arnold also led an expeditionary force from Boston to Quebec and participated in an unsuccessful attack in the Battle of Quebec. On February 22, 1767 he married Margaret Mansfield, by whom he had three sons. Margaret died in 1775.

Arnold was eventually promoted to the rank of brigadier general and in 1776 oversaw the construction of America's first gunships on Lake Champlain, in the town of Whitehall, NY. This earned Whitehall the nickname "Birthplace of the U.S. Navy" and under Arnold's leadership and cunning the new flotilla defeated a vastly superior British enemy fleet near Valcour Island, NY on October 11, 1776.

In 1777, Arnold was passed over by the Continental Congress for a promotion to a major generalship. Although he had no command of his own, he played a vital role in winning the battle by leading a charge through the British line at the Battle of Saratoga. His horse was shot while he was rallying troops. The horse fell on his leg which was shot at Montreal. He was given a new horse by the Continental Congress.

Gen. George Washington put Arnold in charge of Philadelphia, where he met and married Margaret "Peggy" Shippen-Arnold. The Shippen family was well known for its British sympathies. On April 9, 1779 he married Peggy, by whom he had four sons and a daughter.

He was a friend of George Washington and a superior strategist who was well-liked by his men. Nevertheless, his political enemies caused him to be court-martialed several times, notably on June 1, 1779. Arnold was a principled man who felt that the Revolutionary War should be a dispute purely between Britain and her colonies without intervention by France. When General Washington and the Continental Congress made an alliance with France against Britain, he disagreed strongly and began to pass information to British forces. Arnold's Loyalist wife, Peggy Shippen, acted as his agent. Through his wife, Arnold corresponded with British Major John André (a past suitor).

In 1780, he negotiated with British General Henry Clinton to hand over the American fort at West Point, New York to the British for 20,000 sterling (about $1,000,000 today). His plans were discovered when his courier, British Major John André, was captured on September 23, 1780 with incriminating documents. The capture of John André was considered so significant that a special award, known as the Fidelity Medallion, was created by the Continental Congress for those who had participated in John André's capture.

Learning of André's capture, Arnold escaped and joined the British forces. He was appointed Brigadier General in the British Army and engaged Continental forces on a few occasions, but was mostly an insignificant factor in the rest of the war. His one moment of significance occurred on January 5, 1781 when Richmond, Virginia was burned by British naval forces led by Arnold. As for Arnold's wife Peggy, she feigned innocence in the whole affair and with George Washington's permission, was sent to Philadelphia by carriage. However, Arnold's two aides-de-camp at West Point, Richard Varick and David Franks, fell under suspicion for complicity. Both were subsequently cleared and continued to serve the American cause.

Within the United States, the name of Benedict Arnold is a synonym for "traitor." Outside the United States, however, he is thought of in more neutral terms. In Canada and the United Kingdom he is regarded as a traitor who became a patriot, while Americans consider him to have done the reverse. Arnold explained his actions in an open letter titled "To the Inhabitants of America." In a letter to his former friend Washington, he stated, "love to my country actuates my present conduct, however it may appear inconsistent to the world, who very seldom judge right of any man's actions."

Arnold is buried, with his wife and his daughter, in the crypt of St. Mary's Church, Battersea, London, in the uniform of a Continental soldier.