Thrilling proof of a royal friendship that has endured for centuries

Blenheim Palace in Oxfordshire stands as a testament to the historic bond between the Dukes of Marlborough and the British monarchy. Completed in 1722, this ancestral seat owes its existence entirely to the determination of Queen Anne to commemorate the 1st Duke’s glorious victory over the French in 1704 and her long-time friendship with Sarah Churchill – his Duchess and her favourite.

This spring, a gem of an exhibition, Royal Connections Crowns and Coronets, draws on a cache of private letters, intimate photographs and personal gifts from the family archive to remind us that in every reign since, the Marlboroughs and our royalty have been linked by strong ties of friendship.

Sarah’s favourite granddaughter – one Lady Diana Spencer – was close to the children of George II and very nearly became the wife of the Prince of Wales. The 4th Duke shared a passion for astronomy with George III. The 8th Duke and Edward VII fell out over an extra-marital affair and a misguided attempt at blackmail. The 10th Duke and Duchess played host to Edward VIII and Wallis Simpson in the pivotal summer of 1936. The two families, we are told, have been guests at each others’ weddings and godparents to each others’ children.

In Royal Connections, a procession of coronation outfits and souvenirs attest to the Marlboroughs’ presence at every British monarch’s investiture since 1702. In both 1937 and 1953 they were assigned the same seats in Westminster Abbey, right near the front, according to the tickets on show here. Lady Rosemary Spencer-Churchill was a Maid of Honour for our late Queen; while her grandmother Consuelo held the canopy over Queen Alexandra as she was anointed in 1902, a scene that graced the pages of contemporary publications and is recreated with replica costumes in one of the state rooms with surprisingly immersive effect.

Yet it’s the objects that take us back to where the Marlborough’s royal connection began that feel like the crowning glories of this exhibition: the accounts book recording every detail of Queen Anne’s expenditure in Sarah Churchill’s confident hand; or the coronet once worn by Anne and squirreled away by Sarah in its travelling case, stripped of its precious stones and looking all 300 years of its age, but still exuding a thrilling sense of the two women's shared history.

No doubt coronation robes and coronets handed down with the family silver will be on display in stately homes this summer, but it’s treasures like these that elevate Blenheim’s show of royal regalia to another level.

Until July 30. Tickets: 01993 810530; blenheimpalace.com