The present dukedom is unique, in that the first holder of the title created it for himself in his capacity of Lord Protector of the Kingdom of England, using a power granted in the will of his nephew King Edward VI.

This courtesy title is the lowest in rank of all heirs to dukedoms in the peerages of the British Isles, yet the holder's precedence is higher than his title suggests, by virtue of the seniority of the Dukedom of Somerset (the only more senior non-royal duke is the Duke of Norfolk).

1155), a favourite of Empress Matilda and a loyal supporter of her in the war against King Stephen (during which he earned the epithet of the "Scourge of the West"), was given the title Earl of Somerset in 1141.

He was created Earl of Somerset on 10 February 1397; on 9 September 1397, following his marriage to Margaret Holland, daughter of Thomas Holland, 2nd Earl of Kent, he was promoted to Marquess of Somerset,[3] and a few weeks later on 29 September 1397 he was created also Marquess of Dorset.

He was created Duke of Somerset and Earl of Kendal on 28 August 1443 and died less than a year later on 27 May 1444, perhaps by suicide.

Henry's titles were forfeited by act of Parliament; but his brother Edmund Beaufort (c.1439–1471) was styled Duke of Somerset by the Lancastrians.

[3] In 1499 Henry VII nominated his infant son Edmund to the dukedom of Somerset at his baptism, but the child, just over a year old when he died,[3] was probably never formally created a peer.

[9] Robert Carr (c. 1587–1645), born Kerr/Ker, son of Sir Thomas Ker of Ferniehirst, became a favourite of King James VI and I.

Henry had created him Viscount Beauchamp "of Hache" in 1536, at the time of the marriage, and Earl of Hertford in 1537.

[13] On 10 August 1547 he obtained royal letters patent to bear the augmented coat of arms previously granted in 1536 by Henry VIII to Jane Seymour.

On the failure of the junior male line in 1750, Sir Edward Seymour, 6th Baronet of Berry Pomeroy became the 8th Duke of Somerset, as the patent allowed, and his descendants, seated at Maiden Bradley House in Wiltshire, continue to bear the title today.

[15] He was replaced in the minority government of Edward VI by John Dudley, Duke of Northumberland, whose pragmatic style contrasted with Seymour's mixture of idealism and arrogance.

In return for obtaining military help from Ireland he promised Edward the title of Duke of Somerset.

This enabled King Charles II to restore the ducal title to the fourth creation family, the Seymours, who descend from the country's de facto regent, the lord protector in 1547.

Charles I received his support and made him Marquess of Hertford in 1640 and on 13 September 1660, shortly before his death on 24 October, the title of Duke of Somerset was restored to him as its legitimate heir, following its non-existence for 108 years.

When the 5th Duke died unmarried in 1678, the title passed to his brother, Charles Seymour (1662–1748), youngest son of the 2nd Baron Trowbridge.

The 6th duke died 2 December 1748, at Petworth House, Sussex[18] at age 86 leaving the title to his son from his first marriage Algernon Seymour (1684–1750).

The remainder of the earldom was to pass to Sir Hugh Smithson, husband of Algernon's daughter Elizabeth Seymour (bef.

1730–1776), whilst the titles Baron Cockermouth and Earl of Egremont were remaindered to the children of his sister, Lady Catherine Seymour (1693–1731).

Without male issue, on his death in February 1750 these titles therefore passed to different families in accordance with the remainders in the patents of their creation.

The 11th Duke was succeeded by his eldest son Edward Adolphus Seymour (1804–1885) who was created Earl St. Maur, of Berry Pomeroy in 1863.

Had the Earl married Rosina, Harold would have been the heir to his grandfather's dukedom and for this reason Harold tried to find proof that the couple had married whilst they were living in the Netherlands, offering reward of £50 (equal to about £7,000 today)[21] for evidence to support the claim, but was unsuccessful.

[24] Includes dukes of: Albany, Albemarle, Bedford, Cambridge, Clarence, Connaught and Strathearn, Cumberland, Edinburgh, Gloucester, Gloucester and Edinburgh, Hereford, Kent, Kintyre and Lorne, Norfolk, Ross, Somerset, Sussex, Windsor, and York, but only when royally.