MOSTYN, John (1709-79).

Published in The History of Parliament: the House of Commons 1754-1790, ed. L. Namier, J. Brooke., 1964
Available from Boydell and Brewer



30 Dec. 1741 - 1768

Family and Education

b. 1709, 2nd s. of Sir Roger Mostyn, 3rd Bt., M.P., by Lady Essex Finch, da. of Daniel, 7th Earl of Winchilsea; bro. of Savage and Sir Thomas Mostyn, 4th Bt.  educ. Westminster June 1722, aged 13; Ch. Ch. Oxf. 25 June 1728, aged 18.  unm.

Offices Held

Ensign 16 Ft. 1733, capt. 1736; capt.-lt. 2 Ft. Gds. 1742, capt. and lt.-col. 1743; col. army 1747; col. 7 Ft. 1751-4; col. 13 Drag. 1754-8; maj.-gen. 1757; col. 5 Drag. 1758-60, 7 Drag. 1760-3; lt.-gen. 1759; col. 1 Drag. Gds. 1763- d.; gov. Minorca 1768- d.; gen. 1772.

Groom of the bedchamber 1746- d.


Mostyn was a nephew of Thomas, 1st Marquess of Rockingham and a cousin of Charles, 2nd Marquess: he sat for Malton on the Rockingham interest and was a regular Government supporter. He was friendly with Lord Lincoln and attached to Newcastle, Lincoln’s uncle and Rockingham’s friend. Newcastle liked him (he usually addressed him as ‘my dear Jack’), and tried to forward his career; which Mostyn repaid with support in Parliament, assurances of affection, and promises of eternal devotion. He wrote to Newcastle on 11 Oct. 1759: ‘that fatherly affection which your Grace has done me the honour to show me on all occasions makes me as proud of myself as if I really was your son’. And on 7 Mar. 1761: ‘I am yours and yours only, to be blindly and totally directed by you in everything.’1 Politics meant little to him and while Newcastle held office he did not have to think about them.

In 1758 he went with the expedition to St. Cas; from 1759 to 1762 commanded the cavalry in Germany, and during the winter of 1759-60 was acting commander of the British force—‘prodigiously honoured, damnably harassed, and very ill paid’. He was anxious for Newcastle’s advice about the business aspect of his command, and wrote on 26 Feb. 1760:

I have during (I hope the short time) of my having the command of his Majesty’s British forces here, more business than I believe any man in Europe has except your Grace, and what is the worst of it is, that it is all in the writing and reading way, two things I never had patience to bear and that I am afraid I do very ill.

And on 29 Mar.:

I know myself very awkward in business, and have had of late a great deal of the very sort I have least acquaintance with, viz. money matters ... I never drew a warrant in my life or saw one till now.

He was even more concerned about advancement in the army—a matter on which Newcastle could help him little. He wrote on 24 Apr. 1760:

I am most heartily glad to hear of a reinforcement coming to us, but ... I hope no more lieutenant-generals are to come with them ... I stood the last campaign from March to February, without a day’s sickness or an hour out of humour ... but an older lieutenant-general coming over to this army would hurt me more than the whole French army.

In August 1760 the King offered Mostyn the command of General Cope’s regiment, the 7th Dragoons; he accepted with ‘the most humble, most dutiful, and most grateful acknowledgements’, but complained to Newcastle:

Cope had a government, not a Plymouth indeed, but a little Irish government of Limerick, if it was approved of, that I might have had that with his little dirty regiment, it would not pay, but might go towards paying for the extraordinary expenses which a German campaign will make necessary for the colonel to be at ... In short, my Lord, though I accept this regiment as most becomes my duty to my master, if I should by doing it cut the grass under my own feet, and appear to forgo the right I think I have to Bland’s regiment [1st Dragoon Guards] I shall never forgive myself ... If there should be any opening to secure a promise of Bland’s (when the tedious mummy cannot hold any longer together) I know your Grace ... will not let it slip. Do this for me and I will never trouble your Grace with so long, so dull a letter again. Except by your own order you shall never hear anything from me but fun and bawdy, which I will dress up for your Grace’s ear in language as neat as if I was whispering it to a blushing virgin.

To Colonel Richard Peirson he described Bland’s regiment as ‘my great point, my only point’, and added: ‘Tell him [Newcastle] farther that I am extremely sorry he cannot answer for it; but with the humblest submission to his Grace I do think that he might ask it.’ To Lord Barrington, secretary at war, Mostyn gave ‘a modest hint at Bland’s’; to Ligonier, commander-in-chief, ‘a broader hint’:

I have ever looked upon succeeding to a gentleman’s regiment like marrying his widow ... Bland ... fights a palsy so stoutly and lives so miraculously, that in the middle of a campaign (when the most determined f-rs take their precautions) I should, without the least fear or hesitation, take his widow to my arms ... I must own a passion for that lady; I have ogled her most wishfully ever since I came over, and your Lordship knows, we young fellows (till we have our final answer) never despair of winning any lady we set our hearts upon.

Newcastle and Barrington agreed to recommend Mostyn when Bland’s regiment became vacant, and Mostyn did not allow them to forget their promise. Next, he tried to get a military government and wrote to Newcastle on 21 Jan. 1761:

The government of Plymouth is set down at £1289.2.6. per annum and that of Jersey at o–o–o. I write this day to Lord Ligonier to ask it ... I like it the better for those three tremendous noughts.

Newcastle supported him, and continued to use his failing influence on Mostyn’s behalf. ‘As to what relates to Jack Mostyn’, he wrote to Devonshire on 10 Jan. 1762, ‘I have now done justice with my friend to the King; and there I shall leave it.’2

On 3 Oct. 1762 Mostyn assured Newcastle: ‘I am the most faithful of your humble servants and ... I shall ever be so.’ But he was not prepared to follow Newcastle into opposition: he returned to England in autumn 1762, and in a letter docketed 30 Nov. 1762 Bute acknowledged Fox’s ‘excellent account of Granby and Mostyn’. ‘Everybody has a stomach for court favour’, Mostyn once wrote, ‘but I have a taste.’ Naturally, he did not vote against the peace preliminaries in December 1762.3

On 13 May 1763 General Bland died: Mostyn went to the King that day and was given Bland’s regiment. He thanked Newcastle for his help; Newcastle’s reply began:

Though I think I have the greatest reason to take unkindly your late behaviour towards me, not as to the thing itself so much as to the manner; for you cannot imagine that I would have been so unreasonable as to desire you in your circumstances to have done otherwise than you have done.

Mostyn’s defence was sensible, dignified, and sincere:

My manner of doing anything lately has not been so immediately under your Grace’s own eye as I wish it had ... I am never very low and sometimes too high in spirits, but drunk or sober, if ever I could slip in my duty, love and honour for your Grace I should hate myself more than it is in your nature to hate anybody.4

Newcastle seems to have made no reply, and no further letters from Mostyn appear among his papers.

Mostyn did not vote against the Grenville Administration over Wilkes and general warrants. Rockingham in July 1765 classed him as ‘pro’, yet he voted against the repeal of the Stamp Act. ‘What can General Mostyn ... say for being in such a minority?’ wrote James West to Newcastle on 7 Feb. 1766.5 He is not known to have voted against Administration on any other question; to have voted against Rockingham, patron of Malton, within two years of a general election, indicates independence and honest conviction. Newcastle and Rockingham in the winter of 1766-7 classed him as a supporter of the Chatham Administration, but he did not vote in the divisions on the land tax, 27 Feb. 1767, or the nullum tempus bill, 17 Feb. 1768.

In 1768 he had no hope of being returned again by Rockingham, now fixed in opposition. Yet almost at the last moment he secured an honourable and profitable retreat. George Selwyn wrote to Lord Carlisle on 7 Feb. 1768:6

G. Howard has Chelsea [Hospital] in the room of Sir R. Rich ... he exchanged it with Mostyn who has Minorca, which G. Howard was to have had, and is £500 more, but Mr. Howard chose to be in Parliament.

Minorca was worth £730 per annum (£230 more than Chelsea Hospital), but was incompatible with a seat in the Commons.

Mostyn died 16 Feb. 1779.

Ref Volumes: 1754-1790

Author: John Brooke


  • 1. Add. 32897, f. 5; 32919, ff. 495-6.
  • 2. Add. 32902, f. 416; 32904, ff. 98-99, 329-30; 32905, ff. 57-58; 32910, ff. 56, 74, 118, 276-7, 278; 32917, f. 459; 32933, f. 177.
  • 3. Add. 32917, ff. 226-7; 32943, ff. 50-51; Henry Fox mss.
  • 4. Add. 32948, ff. 279, 298, 308-9.
  • 5. Add. 32973, f. 377.
  • 6. HMC Carlisle, 238.