
"Power tends to corrupt, and absolute power corrupts absolutely in such manner that great men are almost always bad men."
Letter to Bishop Mandell Creighton, April 5, 1887 http://oll.libertyfund.org/index.php?option=com_content&task=view&id=1407&Itemid=283. In Figgis, J. N. e Laurence, R. V. Historical Essays and Studies, London: Macmillan, 1907.