SEYMOUR, William (d.1391), of Hatch Beauchamp, Som. and Brobury, Herefs.

Published in The History of Parliament: the House of Commons 1386-1421, ed. J.S. Roskell, L. Clark, C. Rawcliffe., 1993
Available from Boydell and Brewer



Sept. 1388

Family and Education

s. of Sir Roger Seymour of Undy, Mon. by Cecily, er da. of John, 2nd Lord Beauchamp of Som. and Margaret, da. of John, 1st Lord St. John of Basing, coh. of her bro. John, 3rd Lord Beauchamp (d.1361). m. Margaret, da. of Simon Brobury of Brobury, by Joan, da. of Sir Reynold de la Mare, 1s.1

Offices Held


William Seymour was well connected. His father came from an old Monmouthshire family with lands at Undy near Newport, and his mother, Cecily, was the sister and coheir of John, Lord Beauchamp of Somerset, from whom she inherited the manors of Hatch Beauchamp, Shepton Beauchamp and Murifield, with other property in Somerset, as well as estates in Buckinghamshire, Devon and Suffolk. By her gift William received the profits from Hatch Beauchamp but (as he predeceased her) he never enjoyed possession of her other lands. His link with Herefordshire stemmed from his marriage to Margaret de la Mare, who bought him the manor of Brobury in the Wye valley. She was the cousin of the famous Sir Peter de la Mare (Speaker in the Parliaments of 1376 and October 1377) and of his younger brother, Malcolm, who sat as Seymour’s fellow knight of the shire for Herefordshire in the Cambridge Parliament of 1388.2

Apart from this, comparatively little is known about our MP. He is first recorded in 1365, when he was acting as his father’s executor, and he is possibly to be identified with the William Seymour who, in June 1383, became an indentured retainer of John of Gaunt.3 He died on 25 Aug. 1391, whereupon his lands passed to his son, Roger. Three years later (on the death of his paternal grandmother) the latter inherited the Beauchamp properties as well, and in 1400 part of the de la Mare estates also fell to him following the deaths without issue of his mother’s cousins. Roger’s son was Sir John Seymour, from whom descended the Seymour dukes of Somerset.4

Ref Volumes: 1386-1421

Author: Charles Kightly


  • 1. CP, ii. 49-50; xii (pt.i), 59n; CPR, 1388-92, p. 400; C136/73/5.
  • 2. Reg. Trefnant (Canterbury and York Soc. xx), 175; J. Duncumb, Herefs. iv. 43; Peds. Plea Rolls ed. Wrottesley, 248.
  • 3. CPR, 1364-7, p. 51; Reg. Gaunt, 1379-83, i. 21.
  • 4. CFR, xi. 19, 46; CCR, 1392-6, p. 317; C136/73/5.