Sarah Churchill, Duchess of Marlborough
In 1725 the widowed Sarah Churchill, Duchess of Marlborough, became the owner. She added the Marlborough Wing, developed a tiered garden excavated in the sloping hillside and still known as the "Duchess's Garden". It then passed from her grandson, John Spencer, through inheritances to the Dukes of Northumberland who held it until the 1930s. It was then acquired by Alfred Mildmay who carried out major renovations to the building.