John Seymour, 4th Duke of Somerset
John Seymour, 4th Duke of Somerset and 3rd Marquess of Hertford was an English peer and MP.
He was the only surviving son of William Seymour, 2nd Duke of Somerset, and Lady Frances Devereux, and he entered Gray's Inn in 1666. He succeeded his nephew as the 4th Duke of Somerset in 1671. In 1656 he married Sarah, daughter and co-heiress of Sir Edward Alston and widow of George Grimston.
He was elected Member of Parliament for Marlborough in 1661.
He died in 1675, childless, and was buried in Salisbury Cathedral. He was succeeded in the dukedom by his cousin, Francis Seymour. The Marquessate of Hertford became extinct on his death.Ancestry
