MOSTYN, Thomas (by 1543-1618), of Mostyn, Flints. and Gloddaeth, Caern.

Published in The History of Parliament: the House of Commons 1558-1603, ed. P.W. Hasler, 1981
Available from Boydell and Brewer



Family and Education

b. by 1543, 1st s. of William Mostyn by Margaret, da. of Robert ap Hywel of Whittington, Salop. m. (1) Ursula, da. of William Goodman, mayor of Chester, 3s. 2da.; (2) Catherine, da. of Peter Mostyn of Talacre, wid. of Sir Rhys Gruffydd (d.1580), of Penrhyn, Caern., s.p. suc. fa. 1576. Kntd. 1599.2

Offices Held

Sheriff, Anglesey 1574-5, 1587-8, Flints. 1577-8, 1586-7, Caern. 1583-4; j.p. Flints. from c.1577, Caern. from c.1582; dep. lt. and muster master, Flints. from c.1576; custos rot. Caern. from 1596; member, council in the marches of Wales 1602.3


The wide estates and ancient lineage of the Mostyns marked the heir for public service. He was put on the commissions of the peace in his father’s lifetime, and his five periods as sheriff were distributed between three different shires. But parliamentary honours do not appear to have attracted him: he was returned at a by-election for Flintshire in February 1577 to replace his deceased father, but he never stood again, living as a country gentleman, except for a period of military service with Essex in Ireland. It was Essex who knighted Mostyn in Ireland in 1599, but he escaped involvement in the rebellion of 1601. He was on good terms with Lord Burghley, the earls of Pembroke, the Welsh judges, and other leading men of the day. However, he quarrelled with his eldest son Roger, whose marriage in 1597 to a daughter of John Wynn involved the house of Gwydir in the dispute. The estrangement lasted (with temporary reconciliations), till Mostyn’s death.4

In 1584 Mostyn secured a lease for 30 years, on behalf of himself, his son and grandson, of the lordship of Mostyn; but the outright grant of the lordship for which he had engaged John Wynn’s good offices as part of his daughter’s marriage settlement, was withheld until in 1614 it was secured by Wynn’s son Richard, through his influence at court, for Roger Mostyn, passing over the father. It was this family quarrel that involved Sir Thomas in his only important litigation.5

Mostyn died 21 Feb. 1618. His will, dated 10 Dec. 1617, was not proved until 13 June 1625, owing to the heir’s share of the personalty being willed to trustees.6

Ref Volumes: 1558-1603

Author: A.H.D.


Except where otherwise stated, this biography is based upon L. N. V. Lloyd-Mostyn and T. A. Glenn, Mostyns of Mostyn.

  • 1. Did not serve for the full duration of the Parliament.
  • 2. Date of birth estimated from age at father’s i.p.m., Wards 7/18/113; Lansd. 87, f. 138.
  • 3. Cal. Wynn Pprs. 86; Flenley, Cal. Reg. Council, Marches of Wales, 212, 213; Harl. 1974, f. 23; E. Breese, Kal. of Gwynedd, 26; G. Owen, Taylors Cussion, ed. Pritchard (1906), ff. 36, 37; CSP Dom. 1598-1601, p. 403; HMC 13th Rep. IV, 249.
  • 4. Cal. Wynn Pprs. 86; Flenley, 212; Pennant, Tours, ed. Rhys (1883), i. 14; Lansd. 63, f. 95.
  • 5. Augmentations, ed. Lewis and Davies (Univ. Wales Bd. of Celtic Studies, Hist. and Law ser. xiii), 403-4.
  • 6. PCC 65 Clark.