William Seymour, 2nd Duke of Somerset

William Seymour, 2nd Duke of Somerset, KG (1588 – 24 October 1660) was an English nobleman and Royalist commander in the English Civil War.

Early life and background
Seymour was the grandson of Edward Seymour, 1st Earl of Hertford, and Catherine Grey, which thus gave him a distant claim to the throne through the latter's descent from Mary Tudor, younger sister of King Henry VIII of England. His parents were Edward Seymour, Lord Beauchamp of Hache, and Honora Rogers. William was the great-grandson of the first Duke of Somerset.

Secret marriage
Seymour made a secret marriage at Greenwich on 22 June 1610 to Arbella Stuart, daughter of Charles Stuart, 1st Earl of Lennox and Elizabeth Cavendish. Arbella was thirteen years his senior, and the marriage was disapproved of by King James I of England - the marriage of two potential Tudor pretenders to the throne, who were fourth and sixth in line to the English throne, could only be seen as a threat to the ruling dynasty. As a result, William was condemned to life imprisonment in the Tower of London (thus becoming the fourth of five generations of Seymours to spend time in the Tower).

In June 1611, Seymour escaped from the Tower, planning to meet up with Arbella, who also had escaped captivity. They were to flee to the Continent, but bad weather and other circumstances prevented their meeting, and Arbella was recaptured. While she herself was placed in the Tower, William managed to reach safety abroad at Ostend. Arbella remained there until her death in 1615, without ever being reunited with her husband.

Political career
Seymour was elected in December 1620 as Member of Parliament for Marlborough but vacated the seat soon afterwards on succeeding his grandfather as Earl of Hertford in 1621. He became a prominent member of the opposition to King Charles I in the House of Lords, supporting the Petition of Right of 1628, and co-signing the letter of the 12 Peers of 1640, along with his brother-in-law the Earl of Essex.

However, Hertford parted company with the more radical opponents of the King in the Long Parliament in 1641, and was created Marquess of Hertford by the King. In the Civil War, Hertford, along with such figures as Sir Edward Hyde, was a moderate royalist, and throughout sought a compromise settlement, continuing unofficial negotiations with his brother-in-law Essex, who became the Parliamentary commander, throughout the war. He was nevertheless a trusted supporter of the King, who made him guardian of his son the Prince of Wales, and who undertook several important military commands in royalist service over the course of the war, commanding troops from South Wales.

After the end of the First Civil War and the King's imprisonment, Hertford was the most prominent nobleman to remain alongside the king throughout his captivity, and was with him up until his execution in 1649. During the Interregnum, Hertford largely kept himself away from both politics and royalist conspiracies, believing that the monarchy would be restored given time, and that conspiracies would only delay the restoration.

When the Restoration came in 1660, Hertford was restored to all his former positions, and his services in the Royalist cause were further recognised by Charles II, who restored Hertford to his great-grandfather's dukedom of Somerset, which had been forfeited in 1552.

Hertford died at Essex House, London and was buried on 1 November 1660 at Great Bedwyn, Wiltshire. He was succeeded by his grandson William Seymour.

Family
William Seymour married, firstly, 22 June 1610 to his cousin Lady Arbella Stuart (d. 1615), leaving no issue. At the time of their marriage, Lady Arbella was fourth in line to the succession of their cousin, King James I.

He married, secondly, on 3 March 1617 to 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, with seven children:
 * 1) Frances Seymour (?–d. before 1685), married firstly, Richard Molyneux, 2nd Viscount Molyneux, secondly, Thomas Wriothesley, 4th Earl of Southampton as his third wife, and secondly, Conyers Darcy, 2nd Earl of Holderness also as his third wife. From the latter she had issue.
 * 2) William Seymour (1621 – 16 June 1642)
 * 3) Robert Seymour (1622–1646)
 * 4) Henry Seymour, Lord Beauchamp (1626 – 30 March 1654), married Mary Capell and had issue. Ancestors to Princess Alice, Duchess of Gloucester and Sarah, Duchess of York.
 * 5) Lady Mary Seymour (1637 – 10 April 1673), married Heneage Finch, 3rd Earl of Winchilsea and had issue.
 * 6) Jane Seymour (1637 – 23 November 1679), married Charles Boyle, 3rd Viscount Dungarvan and had issue. Ancestors of Elizabeth Bowes-Lyon.
 * 7) John Seymour, 4th Duke of Somerset (1646 – 29 April 1675) married Sarah Alston in 1656. No issue.