Mary Anstey, née Anstey, was born in approximately 1717, to Christopher Anstey (1680-1751) and Mary Thompson (d.1754), at Trumpington, Cambridgeshire. The sister of the poet Christopher Anstey (1724-1805), Mary met Elizabeth Montagu in 1737, presumably during one of her periods at Wimpole in Cambridgeshire, though their extant correspondence spans the period of 1739-1755. In a parallel to the easy exchange of letters on health, social gossip and literature which characterised Montagu's early Bluestocking relationships with the Duchess of Portland (1715-1785) and Anne Donnelan (1702-1762), Montagu's letters to Mary reflect an unaffected friendship. In 1754 Montagu not only hosted Mary at Sandleford, but helped her to secure a house on Queen Street in London, where she lived until her death in 1756.