John Emerich Edward Dalberg-Acton was born on 10 January 1834--much of what I know of Lord Acton is in his connections with John Henry Newman, The Rambler magazine, and the issues of Papal Infallibility at the First Vatican Council. He was very much opposed to ultramontanism, with its emphasis on the authority and the powers of the Pontiff. Acton always opposed the centralization of power, it seems--even supporting the Confederacy over the Union in the American Civil War for the sake of states' rights.
(I know he did not say that "power corrupts" but that "power tends to corrupt".)
Lord Acton seems to have been such a brilliant and knowledgable historian that he was not able really to write a sustained work that matched his genius, at least according to Hugh Chisholm: "Lord Acton has left too little completed original work to rank among the great historians; his very learning seems to have stood in his way; he knew too much and his literary conscience was too acute for him to write easily, and his copiousness of information overloads his literary style. But he was one of the most deeply learned men of his time, and he will certainly be remembered for his influence on others."
The Acton Institute provides some interesting links to works by and about Lord Acton here, including his great unfinished work on the History of Freedom.