John Seymour, 4th Duke of Somerset (before 1646 – 29 April 1675) was an English peer and MP.

He was the only surviving son of William Seymour, 2nd Duke of Somerset

William Seymour, 2nd Duke of Somerset

Sir William Seymour, 2nd Duke of Somerset, KG was an English nobleman and Royalist commander in the English Civil War....

 and Lady Frances Devereux and entered Grays Inn in 1666. He succeeded his nephew as the 4th Duke of Somerset in 1671. He married in 1656 Sarah, daughter and co-heiress of Sir Edward Alston and widow of George Grimston.

He was elected Member of Parliament

Member of Parliament

A Member of Parliament is a representative of the voters to a :parliament. In many countries with bicameral parliaments, the term applies specifically to members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members,...

 for Marlborough

Marlborough (UK Parliament constituency)

Marlborough was a parliamentary borough in Wiltshire, which elected two Members of Parliament to the House of Commons from 1295 until 1868, and then one member from 1868 until 1885, when the borough was abolished.e-1295-1640:-1640-1868:...

 in 1661.

He died in 1675, childless, and was buried in Salisbury cathedral. He was succeeded by his cousin, Francis Seymour

Francis Seymour, 5th Duke of Somerset

Francis Seymour, 5th Duke of Somerset , known as 3rd Baron Seymour of Trowbridge between 1665 and 1675, was an English peer....

.