John Sheffield, 1st Duke of Buckingham and Normanby, was an English poet and Tory politician of the late Stuart period who served as Lord Privy Seal and Lord President of the Council. He was also known by his original title, Lord Mulgrave.

Marquess of Normanby is a title that has been created twice, once in the Peerage of England and once in the Peerage of the United Kingdom. The first creation came in 1694 in the Peerage of England in favour of John Sheffield, 3rd Earl of Mulgrave. He was a notable Tory politician of the late Stuart period, who served under Queen Anne as Lord Privy Seal and Lord President of the Council. In 1703 this first Marquess of Normanby was further honoured when he was made Duke of Buckingham and Normanby. These titles became extinct on the death of the 2nd Duke in 1735.