Peregrine Bertie, 2nd Duke of Ancaster and Kesteven, styled The Honourable Peregrine Bertie between 1686 and 1704, Lord Willoughby de Eresby between 1704 and 1715 and Marquess of Lindsey between 1715 and 1723, was a British politician who sat in the House of Commons from 1708 until 1715 when he was called to the House of Lords.

Robert Bertie, 1st Duke of Ancaster and Kesteven PC, styled 17th Baron Willoughby de Eresby between 1666 and 1701, and known as 4th Earl of Lindsey between 1701 and 1706, and as 1st Marquess of Lindsey between 1706 and 1715, was a British statesman and nobleman.