- 1066 William the Conqueror's troops set sail for England
- 1290 Earthquake in the Gulf of Chihli (Bohai Sea) near China, reportedly kills 100,000 people
- 1540 Society of Jesus (Jesuits) founded by Ignatius Loyola confirmed by Pope Paul III in Rome
- 1779 John Adams negotiates Revolutionary War peace terms with Great Britain
- 1821 Mexican revolutionary forces led by Agustín de Iturbide occupy Mexico City as Spanish withdraw, bringing an end to the Mexican War of Independence
- 1822 French scholar Jean-François Champollion announces that he has deciphered the Rosetta stone
- 1905 The physics journal Annalen der Physik publishes Albert Einstein's paper "Does the Inertia of a Body Depend Upon Its Energy Content?", introducing the equation E=mc².
- 1908 Henry Ford's first Ford Model T automobile leaves the Piquette Plant in Detroit, Michigan
Pope Urban VII dies 13 days after being chosen as the Pope, making his reign the shortest papacy in history.
On September 27, 1590
- 1759 Political activist Thomas Paine (22) weds household servant Mary Lambert (21)
- 1865 Physicist Johannes van der Waals (27) weds Anna Magdalena Smit (18)
- 1876 Poet Frederic Mistral (46) weds Marie Louise Aimee Rivière
- 1920 Prime Minister of Australia Robert Menzies (25) weds Pattie Maie Leckie (21) at Kew Presbyterian Church in Melbourne, Australia
- 1934 Baseball player and manager Leo Durocher (28) weds businesswoman Grace Dozier