306: Constantine I is proclaimed Roman emperor by his troops.
315: The Arch of Constantine is completed near the Colosseum in Rome to commemorate Constantine I's victory.
1547: Henry II of France is crowned.
1603: James VI of Scotland is crowned King of England (James I of England), bringing the Kingdom of England and Kingdom of Scotland into personal union. Political union would occur in 1707.
1755: British governor Charles Lawrence and the Nova Scotia Council order the deportation of the Acadians.
1758: The island battery at Fortress Louisbourg in Nova Scotia is silenced and all French warships are destroyed or taken.
1814: An American attack on Canada is repulsed.
1837: The first commercial use of an electrical telegraph is successfully demonstrated in London by William Cooke and Charles Wheatstone.
1854: Walter Hunt is awarded the first U.S. patent for a paper shirt collar.
1866: Ulysses S. Grant named first general of Army.
1868: Wyoming becomes a United States territory.
1898: The United States seizes Puerto Rico from Spain.
1917: Sir Robert Borden introduces the first income tax in Canada as a "temporary" measure (lowest bracket is 4% and highest is 25%).
1943: Benito Mussolini is forced out of office by the Grand Council of Fascism and is replaced by Pietro Badoglio.
1944: The jet fighter—a Messerschmitt 262—is used in combat.
1946: At Club 500 in Atlantic City, NJ, Dean Martin and Jerry Lewis stage their first show as a comedy team.
1946: An atomic bomb is detonated underwater in the lagoon of Bikini Atoll.
1956: Forty-five miles south of Nantucket, the Italian ocean liner Andrea Doria collides with the MS Stockholm in heavy fog and sinks.
1965: Bob Dylan goes electric at the Newport Folk Festival, signaling a major change in folk and rock music.
1978: Louise Brown, the world's first test tube baby, is born at Oldham General Hospital in England.
1981: Voyager 2 encounters Saturn.
2010: WikiLeaks publishes classified documents about the War in Afghanistan, one of the largest leaks in U.S. military history.