William Seymour 2nd Duke of Somerset
- Born: 1588
- Marriage (1): Arbella Stewart Duchess of Somerset on 22 Jun 1610
- Marriage (2): Frances Devereux on 3 Mar 1616
- Died: 24 Oct 1660, Essex House, London, Middlesex, England at age 72
- Buried: 1 Nov 1660, Great Bedwyn, Wiltshire, England
The Most Noble William Seymour, 2nd Duke of Somerset KG, was the son of Edward Seymour, 1st Earl of Hertford, and Honora Rogers, and the great-grandson of the first Duke of Somerset.
He married, firstly, Arbella Stuart, daughter of Charles Stuart, 1st Earl of Lennox and Elizabeth Cavendish, on 22 June 1610, in a secret marriage.
He married, secondly, Lady Frances Devereux, daughter of Robert Devereux, 2nd Earl of Essex and Frances Walsingham,daughter of Francis Walsingham, on 3 March 1616 at Drayton Bassett and had seven children:
* William Seymour (1621-16 June 1642)
* Robert Seymour (1622-1646)
* Henry Seymour, Lord Beauchamp (1626-30 March 1654), married Mary Capell and had issue.
* Lady Mary Seymour (1637-10 April 1673), married Heneage Finch, 3rd Earl of Winchilsea and had issue.
* Jane Seymour (1637-23 November 1679), married Charles Boyle, Viscount Dungarvan and had issue.
* Frances Seymour (1642-?)
* John Seymour, 4th Duke of Somerset (1646-29 April 1675)
King Charles I created William Seymour Marquess of Hertford in 1641, which was the first creation of that title. During the First English Civil War Seymour commanded Royalist forces from South Wales.
He died at Essex House, London and was buried on 1 November 1660 at Great Bedwyn, Wiltshire. He was succeeded by his grandson William Seymour.
William married Arbella Stewart Duchess of Somerset, daughter of Charles Stewart 1st Earl of Lennox and Elizabeth Cavendish, on 22 Jun 1610. (Arbella Stewart Duchess of Somerset was born in 1575 in England and died in 1615 in Tower of London, London, Middlesex, England.)
William next married Frances Devereux, daughter of Robert Devereux 2nd Earl of Essex and Frances Walsingham, on 3 Mar 1616. (Frances Devereux was born about 1590.)