Lieutenant-General Hugh Percy, 2nd Duke of Northumberland, FRS (14 August 1742 – 10 July 1817), born Hugh Smithson, was the eldest son of the 1st Duke of Northumberland. He assumed the surname of Percy by Act of Parliament along with his father in 1750 and was styled Lord Warkworth from 1750 until 1766.
In 1759, he joined the British Army as a teenager and was a captain of the 85th Regiment of Foot by age 17, an achievement that demonstrated the power of wealth and family standing. He was, nonetheless, a good soldier and fought with distinction in 1762 at the battles of Bergen and Minden. Afterwards he married Lady Anne Crichton-Stuart, daughter of Lord Bute, in 1764. In 1766, his father was granted a dukedom and he was styled Earl Percy.
As a Member of Parliament and the son-in-law of Lord Bute, Percy was promoted to full colonel and appointed an aide-de-camp to the king in 1764, having barely reached his majority. In 1774, he was sent to Boston with the local rank of Brigadier General, Colonel of the 5th Regiment of Foot and commanded the relief column that saved the retreating British forces at the Battle of Lexington and Concord by skillfully using limited artillery rounds to prevent a failed expedition from becoming a major defeat.
He was absent from the field during the Battle of Bunker Hill, perhaps due to a quarrel with General Howe, a man with whom Percy could not get along. The following year, Percy commanded a division during the Battle of Long Island and led the storming of Fort Washington. By 1777, he achieved the rank of Lieutenant General but grew so disgusted with the conduct of the war by General Howe that he resigned his command and left America in 1777 after a dispute over a quantity of hay.
Percy was granted a divorce in Parliament from Lady Anne in 1779 on the grounds of her adultery and immediately married Frances Julia Burrell, with whom he had three daughters and two sons. In 1786 he acceded to the title upon his father’s death and continued his father’s agricultural improvements. For example, when corn prices fell after 1815, he reduced his rents by twenty-five percent. He held twice-weekly gatherings at Alnwick Castle, inviting tenants and local tradespeople. He also assumed command of the Percy Yeomanry Regiment in 1798 and as Colonel of the Royal Horse Guards in 1806. Notorious for a bad temper as well as for being one of the richest men in England, the second Duke of Northumberland died suddenly “of rheumatic gout” in July 1817.
He was succeeded by his son Hugh Percy, 3rd Duke of Northumberland. His half brother was James Smithson whose bequest founded the Smithsonian Institution.