Dictionary of National Biography, 1885-1900/Mostyn, Roger (1675-1739)
MOSTYN, Sir ROGER (1675–1739), third baronet, politician, born in 1675, was the eldest son of Sir Thomas Mostyn of Mostyn, Flintshire, second baronet, by Bridget, daughter and heiress of Darcy Savage, esq., of Leighton, Cheshire. Sir Roger Mostyn (d. 1690) [q. v.] was his grandfather. On 10 Feb. 1689–90 he matriculated from Jesus College, Oxford, aged 15. He was returned as M.P. for Flintshire in December 1701, and in the following August both for Cheshire and for the borough of Flint; he elected to sit for the former. In the next parliament (1705–8) he represented Flintshire, and sat for the same constituency till 1734 (except in 1713, when he served for Flint borough). He was a tory and a supporter of Daniel Finch, second earl of Nottingham [q. v.], whose daughter he married. In 1711 he was appointed paymaster of the marines (Treasury Papers, xci. 70), and was one of the four tellers of the exchequer from 30 Dec. 1714 till 22 June 1716. He voted for tacking on the Occasional Conformity Bill to the Land-tax Bill in 1705, and against the articles of commerce in 1713. He voted against the Peerage Bill in 1719, and Walpole's excise scheme in 1733, and having opposed the Septennial Bill, supported the motion for its repeal in 1734. In consideration of his services and the expenses he incurred as paymaster of the marines he was allowed a sum of 300l. for eight years (ib. ccxlvi. 68). There is also among the 'Treasury Papers' a dormant warrant in favour of Mostyn as controller of the fines for the counties of Chester, Flint, and Carnarvon, dated 31 July 1704. He died on 5 May 1739, at his seat in Carnarvonshire.
Mostyn married, on 20 July 1703, Lady Essex, daughter of Daniel Finch, second earl of Nottingham; she was noted for her beauty, and her portrait, painted by Kneller in 1703, was engraved by J. Smith in 1705 (Noble, ii. 375–6). She died of small-pox on 23 May 1721, leaving issue six sons and six daughters. The eldest son, Thomas (1704–1758), became fourth baronet, with the death of whose grandson Thomas in 1831 the baronetcy expired. Of Sir Roger's younger sons Roger (1721–1775) was canon of Windsor, and Savage, vice-admiral, is separately noticed. Another son, John Mostyn (1710–1779), general, was elected to Westminster School in 1723, and to Christ Church, Oxford, in 1728. He was made captain in the 2nd foot-guards in 1743, aide-de-camp to the king in 1747, colonel of the king's own royal fusiliers in 1751, of the 13th dragoons in 1754, of the 5th dragoons in 1758, and of the 1st dragoons in 1763; major-general in 1757, lieutenant-general in 1759, and general in 1772. He became governor and commander-in-chief of Minorca in 1768, and in 1773 was defendant in an action in London brought by one Anthony Fabrigas, whom he had banished from the island (cf. The Proceedings at Large, London, 1773, fol.) In the parliaments which met in 1747, 1754, and 1761 he sat for Malton, Yorkshire. He was appointed governor of Chelsea Hospital in 1768, was gentleman of the bedchamber to George II and George III, and died in Dover Street, London, on 16 Feb. 1779 (cf. Notes and Queries, 8th ser. i. 362; Welch, Alumni Westmonast. p. 297; Walpole, Memoirs of George III).
[Foster's Alumni Oxon. 1500-1714; Burke's Extinct Baronetage, ii. 120; Boyer's Political State of Great Britain, vi. viii. 530; Gent. Mag. 1739, p. 272; Returns of Members of Parliament; Parl. Hist.; State Papers cited in text.]