Sarah Churchill, Duchess of Marlborough
The Spencers were a family of politicians and art collectors. The Honourable John Spencer was the founder of the collection, having inherited and added to the collection of his maternal grandmother Sarah Churchill, Duchess of Marlborough (1660–1744). George John Spencer was well known as a bibliophile due to his care of and additions to the library at Althorp. He was also a collector of early prints.