Known throughout his career as an MP by the family courtesy title of Marquess of Hartington, he first served under Palmerston and joined Russell’s cabinet in 1866 aged only 34, later serving under Gladstone as a reluctant Chief Secretary for Ireland. He had a long career in the Commons, serving as Liberal, later Liberal Unionist, MP for North Lancashire 1857-68, Radnor 1869-80, North East Lancashire 1880-85 and Rossendale 1885-91. In the wake of Gladstone’s temporary retirement following the Liberal defeat in the 1874 general election, Hartington led the Liberal Party from 1875 to 80. Increasingly unhappy with Gladstone’s Irish policy, Hartington led a breakaway group of Liberal Unionists to oppose the Home Rule Bill and then to support the Conservatives, at first from the opposition benches and then from 1895 in coalition, with Devonshire entering the cabinet. He resigned in 1903 over tariff reform and spent his remaining years in quiet retirement.