John Emerich Edward Dalberg-Acton, 1st Baron Acton, 13th Marquess of Groppoli, (10 January 1834 – 19 June 1902), better known as Lord Acton, was an English Catholic historian, politician, and writer. He is best remembered for the remark he wrote in a letter to an Anglican bishop in 1887: "Power tends to corrupt, and absolute power corrupts absolutely."
