Marquess of Somerset

Dukedom of Somerset
Arms of Seymour, Dukes of Somerset: Quarterly: 1st and 4th, Or on a Pile Gules between six Fleurs-de-Lis Azure three Lions of England (being the Augmentation of Honour granted by King Henry VIII on his marriage with Jane Seymour); 2nd and 3rd, Gules two Wings joined in lure the tips downwards Or (Seymour)
Creation date	1443 (first creation) 1448 (second creation) 1499 (third creation) 1547 (fourth creation) 1660 (fourth creation, restored)
Monarch	Henry VI (first creation) Henry VI (second creation) Henry VII (third creation) Edward VI (fourth creation) Charles II (fourth creation, restored)
Peerage	Peerage of England
First holder	John Beaufort, 1st Duke of Somerset
Present holder	John Seymour, 19th Duke of Somerset
Heir apparent	Sebastian Seymour, Baron Seymour
Remainder to	the 1st Duke's heirs male of the body lawfully begotten
Subsidiary titles	Baron Seymour
Extinction date	1444 (first creation) 1464 (second creation) 1471 (second creation, titular) 1500 (third creation forfeit)
Seat(s)	Bradley House Berry Pomeroy Castle
Former seat(s)	Bulstrode Park
Armorial motto	Foy pour devoir (Faith for duty)

Duke of Somerset is a title in the peerage of England that has been created several times. Derived from the county of Somerset, it is particularly associated with two families: the Beauforts who held the title from the creation of 1448, and the Seymours from the creation of 1547, in whose name the title is still held. 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.

The only subsidiary title of the Duke of Somerset is Baron Seymour, which is used as a courtesy title by the eldest son and heir of the Duke. This courtesy title is the lowest in rank of all heirs to Dukedoms in the peerages of the British Isles, yet a Lord Seymour'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).

Several other titles have been held by the Dukes of Somerset, but have become extinct. These include: Earl of Kendal (created 1443, extinct 1444), Earl of Somerset (created 1397, forfeit 1461), Marquess of Dorset (created 1397, degraded 1399; created 1442, forfeit 1461), Marquess of Somerset (created 1397, degraded 1399), Earl of Dorset (created 1441, forfeit 1461), Viscount Rochester (created 1611, extinct 1645), Viscount Beauchamp of Hache (created 1536, forfeit 1552), Earl of Hertford (created 1537, forfeit 1552; and created 1559, extinct 1750), Marquess of Hertford (created 1640, extinct 1675), Baron Seymour of Trowbridge (created 1641, extinct 1750), Baron Percy (created 1722, separated 1750), Baron Cockermouth (created 1749, separated 1750), Earl of Egremont (created 1749, separated 1750), and Earl St. Maur (created 1863, extinct 1885).