Which British peer and politician born in 1734 was a great-grandson of the 1st Duke of Marlborough?
John Spencer, 1st Earl Spencer John Spencer, 1st Earl Spencer (19 December 1734 – 31 October 1783) was a British peer and politician.
William Cavendish, 2nd Duke of Devonshire William Cavendish, 2nd Duke of Devonshire {'1': ", '2': ", '3': ", '4': "} (1672 – 4 June 1729) was a British nobleman and politician. He was the eldest son of William Cavendish, 1st Duke of Devonshire and Lady Mary Butler. A prominent Whig, he was sworn of the Privy Council in 1707, and served as Lord President of the Council from 1716 to 1717 and 1725 to 1729. He married The Hon. Rachel Russell (1674–1725), daughter of William Russell, Lord Russell on 21 June 1688.