Sir Hugh Percy, originally Smithson, 1st Duke of Northumberland (1715-1786) married in 1740 Elizabeth Seymour, heiress of the Percy property, who was granddaughter of Charles Seymour, 6th Duke of Somerset. He was made a Fellow of the Royal Society in 1736, and in 1756 was made a Knight of the Garter. He was privy councillor and then lord-lieutenant of Ireland under Grenville from 1763-5. He was made duke in 1766, and was Master of the Horse under Lord North from 1778-80. He died in 1786.