Papers of William Cavendish, 4th Duke of Devonshire (1720-1764)

This collection consists of personal papers of William Cavendish, 4th Duke of Devonshire. There is a small number of accounts, including an account book with the covering dates of 1753 - 1768, an extract from an account dated 1758-1759 and Irish Tradesmen's Bills paid by the 4th Duke dating from April-May 1756. There is also some correspondence – primarily a volume titled 'Private Familiar letters' containing outgoing letters of the 4th Duke dating from 1756-61, with an index of recipients. The remaining two items in the collection are a journal kept by the 4th Duke (when Marquess of Hartington) containing notes made during his Grand Tour to France and Italy in 1739-40, and an abstract of his will and codicils dating from 1764.

Born in 1720, William Cavendish was the eldest son of William Cavendish, 3rd Duke of Devonshire, and his wife Catherine (née Hoskyns). From 1729, when his father succeeded to the dukedom, he held the title Marquess of Hartington. He was probably educated at home before undertaking the grand tour to France and Italy in 1739-40, accompanied by his tutor, the Reverend Arthur Smyth.

The Cavendish family was at the heart of the Whig party that dominated politics, and a career in politics was the inevitable destiny for Cavendish, as heir to one of the premier dukedoms in the country. As soon as he came of age he was elected to the House of Commons in May 1741 as MP for Derbyshire, the family seat, and adopted his father's allegiance to the prime minister, Sir Robert Walpole. After Walpole's resignation in 1742, he sided with Walpole's political heirs, the Pelham faction, led by Henry Pelham and his brother the Duke of Newcastle, and strongly supported their attempts to fashion a viable administration over the next four years.

On 27 March 1748 Cavendish married Lady Charlotte Elizabeth Boyle, Baroness Clifford of Londesborough (1731-1754), the third but only surviving daughter of Richard Boyle, third Earl of Burlington (1694-1753), and his wife, Dorothy Savile (1699-1758). The match had been planned during the couple's childhood, although Cavendish's mother disapproved. Despite her fears, the marriage proved to be happy, albeit short; Charlotte died of smallpox six years later, on 8 December 1754.

They had four children: William Cavendish, later fifth Duke of Devonshire (1748-1811); Dorothy (1750-1794), who married William Bentinck, third duke of Portland; Richard (1752–1781), MP for Lancaster and then Derbyshire; and George (1754–1834), MP for Knaresborough, then Derby, who became first Earl of Burlington of the second creation in 1831. It was a politically advantageous marriage, as Charlotte's inheritance on her father's death in 1754 included vast estates in Yorkshire and Ireland, as well as electoral interests over the two parliamentary seats at Knaresborough and the Irish parliamentary constituency of Lismore Town. Burlington's villa at Chiswick, and Burlington House in Piccadilly also passed into the Devonshire family. Burlington was an architect and a great connoisseur of the arts, and the inheritance also included his library (containing many important architectural books and drawings), as well as many paintings and the entire contents of his houses.

With his political standing enhanced by his marriage, Cavendish took his seat in the Lords in 1751, which enabled him to accept the mastership of the horse and a cabinet seat from Pelham; he had earlier declined the governorship of the new Prince of Wales, the future George III. He was appointed to these offices and sworn of the privy council on 12 July. Following Pelham's death in 1754 he adhered closely to Newcastle, who appointed him lord lieutenant of Ireland in March 1755. He outlined his policy of reconciling the rival factions in Ireland in a letter to Newcastle, dated 4 October 1755: 'My scheme is if possible to govern this country without a party and make those that receive favours from the Crown think themselves obliged to it and not to their party here'. His policy paved the way for the decisive viceroyalty of the fourth Viscount Townshend in the 1760s.

On 5 December 1755 Cavendish succeeded as fourth Duke of Devonshire. He returned to England in October 1756 at a time of conflict with France and political instability at home. Fox's resignation that month triggered the end of Newcastle's administration, which had been worn down by military failures. Pending a more permanent arrangement, whereby William Pitt could be reconciled with Newcastle, George II summoned Devonshire to form an interim ministry to avert government collapse and to manage the war with France. On 6 November, Devonshire was appointed First Lord of the Treasury (or Prime Minister) and Pitt succeeded Fox, who had been unable to form a viable ministry, as Secretary of State for the South.

However, the Devonshire/Pitt ministry proved short-lived, and it was fatally damaged in April 1757 when Pitt resigned, along with his cousin Temple. After two months of protracted negotiations the Newcastle/Pitt coalition succeeded to office on 29 June, a coalition that led Britain to victory over France.

Devonshire became Lord Chamberlain in the coalition but retained a seat in the inner cabinet, where his integrity, family standing, and friendship with leading Whigs allowed him to calm the rancour of party politics and personality differences. This was especially important after the accession of George III in October 1760 and the advent of his mentor, Lord Bute, whose rapid advancement threatened to undermine Whig hegemony and destabilize governmental politics. Throughout 1761 and 1762, during the peace negotiations with France, Devonshire was a key factor in maintaining the ministerial harmony necessary for achieving peace. During the momentous months from September 1759 to October 1762 he kept a diary which offers keen insights into the decision-making process and general diplomatic affairs of the time.

When Newcastle resigned in May 1762 Devonshire did not follow him out of office but showed his solidarity by refusing to attend cabinet. This anomalous situation, whereby he retained his office yet absented himself from the business of government, could not be tolerated for long, and following a disagreement with Bute over the final peace treaty, he resigned as Lord Chamberlain on 28 November 1762. George III expressed his extreme displeasure at his conduct a few days later when, with his own pen, he struck Devonshire's name from the list of privy councillors, a rare gesture that ended Devonshire's political career. In October 1764, the King dismissed him as Lord Lieutenant of Derbyshire, an office that had been held continuously by the Cavendishes since George I's accession.

Outside of his political life, the Fourth Duke continued to build on changes made by his father to the gardens and park at Chatsworth: he appointed the architect James Paine to design a new stable-block to the north of the house, and an elegant three-arch bridge across the widened River Derwent which was angled to provide a striking view of the house from the entrance drive. Paine also designed a one-arch bridge and a water mill located in the south of the park, and made a number of changes to the house itself, creating the present North entrance in place of the former kitchen, and providing a new service range to the north (demolished by the Sixth Duke when the present North Wing was built in the 19th century). But the Fourth Duke's most important change was to call in the famous landscape gardener Lancelot 'Capability' Brown, to sweep away the First Duke's formal gardens around the house and to surround it with a carefully planned and planted romantic landscape.

The Duke's final months were spent at Spa, Germany, in a state of deteriorating health. He died there on 2 October 1764, aged forty-four, and was buried next to his wife in All Saints', Derby.

Principal source: Karl Wolfgang Schweizer, 'Cavendish, William, fourth duke of Devonshire (bap. 1790-d. 1764)', Oxford Dictionary of National Biography (Oxford: Oxford University Press, 2004). By permission of Oxford University Press.

The material has been arranged into four series, as follows:

• DF2/1: Accounts, 1753 – 1768
• DF2/2: Correspondence, 1756 – 1751
• DF2/3: Journal, 1740
• DF2/4: Official Papers of William Cavendish, 4th Duke of Devonshire, 1764 (will and codicils)

The collection is open for consultation. Access to the archive at Chatsworth is by appointment only. For more information please visit the website.

The material was extant in The Devonshire Collection prior to 1 August 2011.

An item-level catalogue of the collection in PDF format can be found on the Chatsworth website.

Copies of material in the archive can be supplied for private study and personal research purposes only, depending on the condition of the documents.

Most of the material remains in the copyright of Chatsworth House Trust, but a minority is also subject to third-party copyright. It is the responsibility of researchers to obtain permission both from Chatsworth House Trust, and from the any other rights holders before reproducing material for purposes other than research or private study.

Most of the material in the collection was created or acquired by William Cavendish, 4th Duke of Devonshire, and remained within the family; its exact archival history is unknown.

Further correspondence of the 4th Duke of Devonshire can be found in the 4th Duke's Correspondence Series (GB 2495 CS4); and in a bound volume amongst the papers of William Cavendish, 3rd Duke of Devonshire (see GB 2495 DF1/1/1).