The largest part of this series is made up of letters written by William Cavendish to his wife Rachel (née Russell) whilst he was Lord Cavendish and from 1694, Marquess of Hartington and later (1707) as 2nd Duke of Devonshire.
The topics of the letters include: intention to hire a yacht to travel to Brussells which his father insists on without Cavendish having time to see his wife; a picture he is creating for Lady Russell; lack of news being delivered beyond Dover; the whereabouts of French and Dutch fleets; wishes from his brother to Lady Cavendish; his wishes to Lord Bedford, his sister Catherine and Lady Russell; the Prince's army in the West; more fleets being prepared from Holland; post being stopped from Nieuport for fear of interception by the French seeking information about the troops of the Prince of Orange; his travel from Venice to Rome seeing palaces and antiquities; orders from his father to leave Rome after Easter; the restored health of Lord Russell; his onward journey from Padua delayed due to the heat; his return to England; his wish to be in Lady Cavendish's company whilst at Burleigh; the "Beavor" [Belvoir] wedding; Lady Catherine Manners and Lord Roos; a pretty fairing from Woburn; hunting including killing a fox; having a cold; lodgings for Lady Cavendish's brother at Oxford; missing Newmarket in favour of hunting; seeing Lady Orford and Sir John Woodhouse at Newmarket; his desire to hear from Lady Hartington; Lady Hartington's headache and toothache; his recovered leg after his accident; poor weather for fox-hunting; Mrs Mainwaring's company for Lady Hartington; a visit to Hardwick and Derby electioneering; a message to be passed on to the Duke of Devonshire that Lord Rutland gave his son £500 for charges of the election and Lord Hartington fears without a similar sum he will not be able to bring all the freeholders to the election to vote; a letter from Mr Eyre requesting the Duke of Devonshire's interest for him and Sir Thomas Willoughby; being kept up playing "whisk" [whist] with his father and Mr James and Mr Charleton; Lady Hartington's brother's travel plans to Cambridge via Burleigh; his request for Lady Hartington to join her husband and the Duke of Bedford where they are in the country [Chatsworth?]; his promise to send Moore to meet Lady Hartington on the journey from Woburn; Lord Hartington's intention to come to Devonshire House via Lord Carlisle's house in Hampshire for some sport; his intention to remain in the country a few more days for better hunting weather; all the ladies including the Duchess of Somerset and the Duchess of Richmond staying in the country until their husbands have received the King's leave to bring them to London; the Duchess of Richmond's intention to stay longer in the country due to the benefits of the air on "a breeding lady" and this being a secret; Lady Vaughan's inability to keep a secret; Lord Hartington insisting Lady Hartington should know of his affairs as he saw the letters he received; elections in Derby and Lord Roos standing for Leicestershire; Lord Hartington's brother standing in the election; Lord Ferrers providing a vote if the Duke speaks to him; John Phillips providing information on where to direct letters whilst Lord Hartington is travelling; travelling into the East, West and North Ridings of Yorkshire; intention to stop at Belvoir to see Lady Hartington's sister; Lord Hartington's lack of time to see Chatsworth; requesting news of the Duchess of Bedford being brought to bed safely; travelling to town with Lord Orford; Lord Exeter's delayed journey; Kenton taking his problem to Mr Walter; hot weather; a description of his tour of Scotland including a Highlanders' camp upon a great heath; the Duke of Rutland's children to have the King and Queen as godparents; Lord Galloway's rheumatism; painting the sashes of the house; illness of Kate; gout in his elbow; removes at court concerning Lord Stanhope, Lord Sunderland, Old and young Craggs, Mr Lechmere, Mr Addison and Mr Cockburn.
The other material in this group pertains to the roles and activities of William Cavendish and includes:
- two certificates of William Lord Hartington's admittance as Captain of the Yeomen of the guard to the King and Queen, dated 29 January and 15 June 1702;
- an order for the preservation and goverment of Needwood Forest and Chase, Stafford, made by the Duke of Devonshire, dated 1708;
- a note of the legacy of the 1st or 2nd Duke of Devonshire;
- a receipt from the Agent of the Earl of Carlisle for the payment from the Duke of £200;
- a memorandum on jewels belonging to the Duke of Devonshire, kept by Mr Savile, in 1711 and discovered at Mr Tanckred's in 1719;
- two bills to the Duke of Devonshire for furniture bought in 1725;
- a letter to William Capell, 3rd Earl of Essex concerning two tables of Derbyshire marble;
- a receipt from John Vanbrugh, for 100 guineas paid toward building Haymarket theatre.