Archibald St Maur, 13th Duke of Somerset

Archibald Algernon Henry St. Maur, 13th Duke of Somerset (né Seymour; 30 December 1810 – 10 January 1891) was an English aristocrat.

He was born at is family's home on Park Lane, Mayfair, the second son of Edward St. Maur, 11th Duke of Somerset and Lady Charlotte Douglas-Hamilton. He was also a baronet. His motto, Foy Pour Devoir "Faith for Duty", has been adopted by HMS Somerset (IV) by permission.

He was baptized on 17 June 1811 at St. George's, Hanover Square, London,^[1] and in 1885 succeeded his elder brother Edward Seymour, 12th Duke of Somerset, whose sons predeceased him. In his younger years, he had served as a captain in the Royal Horse Guards.^[2] He spent much of his life at Burton Hall, in The Wolds, managing the estate.^[3] He served as High Sheriff of Leicestershire for 1844.

Archibald died at his London home at 28 Berkeley Square,^[4] unmarried and childless. He was buried in the churchyard at Maiden Bradley, Wiltshire on 16 January 1891.^[5] A memorial in the style of a grave was erected in the churchyard at Berry Pomeroy, Devon. His titles passed to his brother, Algernon St. Maur.