On 12 July 1643, parliament commissioned him as sergeant major general for North Wales under an ordinance (renewed and extended in 1644 and 1645) which empowered him to raise troops and to distrain on delinquents’ estates for the expenses, and guaranteed the £5,000 he initially advanced, with any further sums he could raise on his personal credit. He was later allotted the confiscated property of metropolitan recusants and delinquents, including that of shareholders in his uncle's New River Company. These financial arrangements were put in force at the expense of local ‘delinquents’ immediately on the reduction of North Wales (document of 10 Feb. 1646 in Brogyntyn unscheduled coll., N.L.W.); but Myddelton claimed to have been left £35,000 out of pocket. Meanwhile, after a successful border campaign (28 July to 7 Nov. 1643) in collaboration with Thomas Mytton and Sir William Brereton, his first incursion into North Wales (via Holt Bridge) had been cut short by the resistance of William Salusbury (q.v.) at Denbigh and the landing of troops from Ireland on the Flintshire coast (18 Nov.), his only lasting gains being a few Welsh recruits and the bullets made from the organ pipes at Wrexham, his headquarters; but after delays caused by recruiting and refitting (till May 1644) and by mutinies and the manoeuvres of Rupert (which kept him chafing on the border till August), he entered Montgomeryshire, came to terms with Herbert of Cherbury (q.v.) for the surrender of Montgomery castle, which he defended, in a major victory (17 Sept.) surprised and took lord Powis (see under Herbert) in his castle (2 Oct.), which he placed under Sir John Price (q.v.) [No article found], defeated at Machynlleth (27 Nov.) an attempt to intercept reinforcements from South Wales (27 Nov.), and won his first footing in Radnorshire (Dec.), but failed to capture his own castles of Ruthin and Chirk or to gain a footing in Denbighshire. The Self-Denying Ordinance of 3 April 1645 recalled him to Westminster and transferred his command to Mytton (12 May), though he did not actually quit the field until June.
He continued to co-operate with the dominant Puritan faction, showing, according to archbishop John Williams (q.v.), much ruthlessness in ejecting Welsh ministers who refused the Covenant (which he had taken on 22 Sept. 1643), even when there was no one to replace them. He was again entrusted with the defences of North Wales (16 June 1648) in the second Civil War, though the actual campaigning was done by Mytton. But he opposed the king's trial and was expelled from the House in ‘Pride's Purge’ (Dec. 1648), retiring to Chirk. Rumours, in March 1651, of his dealings with Charles II through the earl of Derby, led parliament to put a garrison into his castle, and it was not withdrawn till he had given heavy sureties of his loyalty to the Commonwealth [16 May 1651 to 25 March 1656]. This deterred him from accepting Charles's invitation from Stoke (17 Aug.) to join him on his march down the border (Whitelock, Memorials, iii, 335). [He signed the North Wales petition against the Propagation in July 1652 (Cal. Wynn Papers, 1988), and helped to support the ejected minister of Wrexham, but defended Chirk for the Protectorate when plots were rife in the spring of 1655 (Thurloe State Papers, iii, 209, 298)]. After going for a time into hiding in England, he lived a country gentleman's life at Chirk, developing the coal on his estate and attending an occasional horse race or cock fight, but on 7 Aug. 1659, he joined Sir George Booth in raising Cheshire and North Wales, proclaimed Charles II at Wrexham (C.J., vii, 753; cf. Cal. S. P. Dom., 1659-60, 162), was declared a traitor (9 Aug.), shared in Booth's defeat by Lambert near Nantwich (18 Aug.), but evaded capture and was condemned to sequestration. Before the order could be made effective, he had been recalled to Westminster with the expelled members of the Rump (21 Feb. 1660) and on 27 Feb. the vote for his sequestration was suspended; but the dismantling of his castle had been carried far enough to make it uninhabitable till 1672, the family living meanwhile at Cefn-y-wern. Restored to the militia commission for his county in March 1660, and elected to represent it in the Convention Parliament next month, he again proclaimed Charles II at Wrexham (12 May) and opposed the promotion of John Glynne (q.v.) as one who had accepted office under the regicides (Cal. Wynn Papers, 2240). Successive attempts to buy the lordship of Ruthin from the Crown were foiled by the opposition of the freeholders in Sept. 1660 and the plan was not realised till 1677. He d. at Cefn-y-wern on 22 Jan. 1667. He counted himself Welsh, though he probably could not speak the language. [Although he co-operated with ‘sectaries’ he was himself a loyal Anglican, and his ritualistic practices were often a source of suspicion to his colleagues (Richard Baxter, Penitent Confession, 1691, 30; Myddelton, Chirk Castle Accts, 1605-69, x; N.L.W., Wynnstay MSS. (unscheduled coll.)).]
Emeritus Professor Arthur Herbert Dodd, M.A., (1891-1975), Bangor