285 :Diocletian appoints Maximian as Caesar, co-ruler.
306 :Constantine I proclaimed Roman emperor by his troops.
864 :Edict of Pistres of Charles the Bald orders defensive measures against the Vikings.
1139 :Battle of Ourique: The independence of Portugal from the Kingdom of León and Castile declared after the battle against the Almoravids.
1261 :The city of Constantinople is recaptured by Nicaean forces under the command of Alexios Strategopoulos, thus re-establishing the Byzantine Empire.
1536 :Sebastián de Belalcázar on his search of El Dorado found the City of Santiago de Cali.
1538 :The City of Guayaquil is founded by the Spanish Conquistador Francisco de Orellana and given the name Muy Noble y Muy Leal Ciudad de Santiago de Guayaquil.
1547 :Henry II (France) crowned.
1567 :Don Diego de Losada founds the city of Santiago de Leon de Caracas, modern-day Caracas, the capital city of Venezuela.
1593 :Henry IV of France publicly converts from Protestantism to Roman Catholicism.
1603 :James VI of Scotland is crowned first king of Great Britain.
1693 :Ignacio de Maya founds the Real Santiago de las Sabinas, actual Sabinas Hidalgo, Nuevo León, México.
1722 :Three Years War begins along Maine and Massachusetts border.
1755 :The decision to deport the Acadians takes place in Halifax. Thousands of Acadians are sent to the British Colonies in America, France and England. Some later moved to Louisiana, while others later resettled in New Brunswick.
1758 :Seven Years' War: The island battery at Fortress Louisbourg in Nova Scotia is silenced and all French warships are destroyed or taken.
1759 :French and Indian War: In Western New York, British forces capture Fort Niagara from French, who subsequently abandon Fort Rouillé.
1792 :The Brunswick Manifesto is issued to the population of Paris promising vengeance if the French Royal Family is harmed.
1795 :The first stone of the Pontcysyllte Aqueduct is laid.
1797 :Horatio Nelson loses more than 300 men and his right arm during the failed conquest attempt of Tenerife Island (Spain).
1799 :At Aboukir in Egypt, Napoleon I of France defeats 10,000 Ottomans under Mustafa Pasha.
1814 :War of 1812: Battle of Lundy's Lane - Reinforcements arrive near Niagara Falls for General Riall's British and Canadian forces and a bloody, all-night battle with Jacob Brown's Americans commences at 18.00; Americans retreat to Fort Erie.
1824 :Costa Rica annexes Guanacaste from Nicaragua.
1837 :The first commercial use of an electric telegraph was successfully demonstrated by William Cooke and Charles Wheatstone on 25 July 1837 between Euston and Camden Town in London.
1853 :Joaquin Murietta, famous Californio bandit known as Robin Hood of El Dorado, is killed.
1861 :American Civil War: The Crittenden-Johnson Resolution is passed by the U.S. Congress stating that the war is being fought to preserve the Union and not to end slavery.
1866 :The U.S. Congress passes legislation authorizing the rank of General of the Army (now called 5-star general). Lieutenant General Ulysses S. Grant becomes the first to have this rank.
1868 :Wyoming becomes a United States territory.
1869 :The Japanese daimyo begin returning their land holdings to the emperor as part of the Meiji Restoration reforms. (Traditional Japanese Date: June 17, 1869
1894 :The First Sino-Japanese War begins when the Japanese fire upon a Chinese warship.
1897 :Writer Jack London sails to join the Klondike Gold Rush where he will write his first successful stories.
1898 :The United States invasion of Puerto Rico begins with U.S. troops landing at harbor of Guánica, Puerto Rico [The land invasion, proper, began that day: Sea-based bombardment and shelling of the capital city of San Juan had been occurring since May of 1898.
1907 :Korea becomes a protectorate of Japan.
1908 :Ajinomoto is founded. Kikunae Ikeda of the Tokyo Imperial University discovers that a key ingredient in Konbu soup stock is monosodium glutamate (MSG), and patents a process for manufacturing it.
1909 :Louis Blériot makes the first flight across the English Channel in a heavier-than-air machine (Calais to Dover) in 37 minutes.
1917 :Sir Thomas Whyte introduces the first income tax in Canada as a temporary measure (lowest bracket is 4% and highest is 25%).
1920 :Telecommunications: First transatlantic two-way radio broadcast takes place.
1925 :Telegraph Agency of the Soviet Union (TASS) is established.
1934 :Nazis assassinate Austrian Chancellor Engelbert Dollfuss in a failed coup attempt.
1940 :General Guisan orders the Swiss Army to resist German invasion and make surrender illegal.
1943 :World War II: Benito Mussolini is forced out of office by his own Italian Grand Council and is replaced by Pietro Badoglio.
1944 :World War II: Operation Spring - One of the bloodiest days for Canadians during the war: 18,444 casualties, including 5,021 killed.
1946 :At Club 500 in Atlantic City, New Jersey, Dean Martin and Jerry Lewis stage their first show as a comedy team.
1946 :Operation Crossroads: An atomic bomb is detonated underwater in the lagoon of Bikini atoll.
1952 :The U.S. non-incorporated colonial territory of Puerto Rico adopts a constitution of local-limited powers, approved by the United States Congress in convention ofthen-current International Law.
1956 :45 miles south of Nantucket Island, the Italian ocean liner SS Andrea Doria collides with the MS Stockholm in heavy fog and sinks the next day, killing 51
1958 :The African Regroupment Party (PRA) holds its first congress in Cotonou.
1961 :John F. Kennedy speech emphasizes that any attack on Berlin is an attack on NATO.
1969 : Vietnam War: US President Richard Nixon declares the Nixon Doctrine, stating that the United States now expects its Asian allies to take care of their own military defense. This was the start of the Vietnamization of the war.
1973 :Soviet Mars 5 space probe launched.
1978 :The Cerro Maravilla Incident occurs.
1983 :Black July: 37 Tamil political prisoners at the Welikada high security prison in Colombo were massacred by the fellow Sinhalese prisoners.
1984 :Salyut 7 Cosmonaut Svetlana Savitskaya becomes the first woman to perform a space walk.
1993 :Israel launches a massive attack against Lebanon in what the Israelis call Operation Accountability, and the Lebanese call Seven-Day War.
1993 :The St James Church massacre occurs in Kenilworth, Cape Town, South Africa.
1994 :Israel and Jordan sign the Washington Declaration, which formally ends the state of war that has existed between the nations since 1948.
1995 :A gas bottle exploded in station Saint Michel of line B of the RER (Paris regional train network). Eight were killed and 80 wounded.
1997 :K.R. Narayanan is sworn-in as India's 10th president and the first Dalit— formerly called untouchable to hold this office.
2000 :Air France Flight 4590, a Concorde supersonic passenger jet, F-BTSC, crashes just after takeoff from Paris killing all 109 aboard and 4 on the ground.
2007 :Pratibha Patil is sworn in as India's first woman president