Derby, Edward Henry Stanley, 15th earl of (därˈbē) [key], 1826–93, British politician, son of the 14th earl. Although more liberal than his father, he held several positions in the latter's administrations, including foreign secretary (1866–68). He was foreign secretary again (1874–78) under Benjamin Disraeli, but resigned in protest against Disraeli's intervention in the Russo-Turkish war (1878). Derby later (1880) formally shifted his allegiance to the Liberal party and was colonial secretary (1882–85) under William Gladstone. He broke with the Gladstonian Liberals over the issue of Home Rule for Ireland and led the Liberal Unionists in the House of Lords until his retirement in 1891.