Acton, Sir John, 1st Baron Acton (1834–1902). Historian and liberal Roman catholic. From an old Shropshire family on his father's side, Acton had a German mother and was brought up as a Roman catholic mainly on the continent, and especially in Germany. He first came to public attention writing articles for liberal catholic periodicals, many of them reprinted in The History of Freedom and Lectures and Essays in Modern History. He reported the 1870–1 Vatican Council from a liberal catholic perspective, opposing papal infallibility. Acton was an MP 1858–65 (for Carlow) and was created a peer by Gladstone in 1869. He was a lord-in-waiting at court, 1892–5. To this point, Acton had a great reputation as a cosmopolitan historical polymath, whose great work on the history of liberty awaited publication. In 1895 he became regius professor at Cambridge, and delivered a famous inaugural lecture (11 June 1895). He edited, but did not contribute to, the Cambridge Modern History, which set the pattern for a century for the Cambridge approach to multi-authored textbooks. Acton never finished any of his own grand projects (his note-boxes in Cambridge University Library reflect a mind almost mad with compilation) but his published output was far larger than is often allowed. Central to Acton's interest in history was the role of freedom and the capacity of the individual, if correctly imbued with moral and political righteousness, to promote freedom and progress in church and state. Gladstone, for Acton, most nearly epitomized this capacity. Though not an easy author to read, Acton was a sharp epigrammist; his most famous epigram—‘Power tends to corrupt and absolute power corrupts absolutely’—was written in a letter to Mandell Creighton on 3 April 1887.

H. C. G. Matthew