These letters from Sarah Churchill (née Jenyns), Duchess of Marlborough are written over a period of seventeen years to Henry Boyle, Lord Carleton and Secretary of State, Rachel Cavendish (née Russell), Duchess of Devonshire and Lady Anne Spencer. Some are written by an amanuensis owing to the Duchess's poor handwriting and trouble with her eyes.
Topics of the letters to Henry Boyle include: her disagreement with a decree and "printed libel" by John Vanbrugh and her intention to bring her cause to court; appreciation for his correspondence; letters sent to the 1st Duke of Marlborough by Queen Anne; and an invitation to Boyle to visit her in Windsor. She defends the 1st Duke of Marlborough against the accusations made against him regarding the payment for works at Blenheim Palace, with reference to the labourer's court case. She accuses Vanbrugh and others of overcharging for their work. Sarah refers to Blenheim as a "Publick Building" & "Heap of Stones".
Topics of the letters to Rachel Cavendish, Duchess of Devonshire include the case against John Vanbrugh's "printed libel" about the Duke and Duchess of Marlborough. Sarah has sent the Duke of Devonshire details of the Duke of Marlborough's legal case with the labourers of Blenheim Palace over payment for the build. Sarah refers to Vanbrugh's libel printed against the Duke which she criticises for its inaccuracies. She details Vanbrugh's career and how the Duke of Marlborough sought to ease the architect's financial hardships. She apologises for her lame hand which prevents her from writing herself.
She also writes with a response to the Duke of Bedford's Bill and an explanation behind the political commentary on it she has also sent [not present with this letter] which she discussed with a legal expert. Sarah continues to discuss the Duke of Bedford's guardianship believing the Duke of Devonshire more appropriate than the Duke of Bridgewater who was his father-in-law.
To Lady Anne Spencer she writes about the Duke of Bedford whose character she praises, and views on his guardianship and the character of the Duke of Bridgewater.