| 1834 | Acton born in Naples | |
| 1837 | Death of his father, Sir Richard Acton | |
| 1840 | Mother remarries Lord Leveson Gower, later second Earl Granville | |
| 1843-48 | Acton boarded at Oscott under Wiseman | |
| 1850 | To Munich studying under Ignaz von Dollinger | |
| 1853 | Journey to USA | |
| 1857 | To Rome with Dollinger | |
| 1858-62 | Part-owner and contributor to liberal Catholic Rambler | |
| 1859-65 | MP for Carlow | |
| 1862 | “Nationality” and “The Protestant Theory of Persecution” | |
| 1864 | Pius IX's Quanta Cura and Syllabus of Errors | |
| 1864-68 | Acton's extensive archival researches | |
| 1865 | Acton marries Countess Marie von Arco-Valley | |
| 1865 | Manning appointed Archbishop of Westminster | |
| 1865-66 | MP for Bridgnorth (GH, 93) | |
| 1869 | “The Massacre of St. Bartholomew” | |
| 1869 | Created Baron Acton by Gladstone | |
| 1869-70 | The Vatican Council | |
| 1874-75 | Gladstone publishes three anti-Vatican articles | |
| 1874 | Acton responds in four letters to The Times | |
| 1875 | Acton fears excommunication. Is spared | |
| 1876 | Gladstone launches crusade against Bulgarian atrocities | |
| 1877 | “Freedom in Antiquity” and “Freedom in Christianity” | |
| 1879-80 | Gladstone's Midlothian campaign | |
| 1880-85 | Advisor to Gladstone's second ministry and advocate of Irish home rule | |
| 1889 | Review of James Bryce's American Commonwealth | |
| 1892-95 | Lord in Waiting to Queen Victoria | |
| 1895 | Appointed Regius Professor of Modern History at Cambridge. Delivers lectures on modern history and the French Revolution. Editor of Cambridge Modern History | |
| 1902 | Death at Tegernsee | |
| 1904 | Acton-Mary Gladstone correspondence published | |
| 1906 | Cardinal Gasquet edits Acton-Simpson correspondence | |
| 1931 | Herbert Butterfield's Whig Interpretation of History | |
| 1952 | Gertrude Himmelfarb's Lord Acton. First full biography |
Source: Hugh, Tulloch, Acton (London: Weidenfeld and Nicolson, 1988),ix.