285 – Diocletian appoints Maximian as Caesar, co-ruler.
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 over Maxentius at the Milvian Bridge.
864 – The Edict of Pistres of Charles the Bald orders defensive measures against the Vikings.
1137 – Eleanor of Aquitaine married Prince Louis, later King Louis VII of France, at the Cathedral of Saint-André in Bordeaux.
1139 – Battle of Ourique: The Almoravids, led by Ali ibn Yusuf, are defeated by Prince Afonso Henriques who is proclaimed King of Portugal.
1261 – The city of Constantinople is recaptured by Nicaean forces under the command of Alexios Strategopoulos, re-establishing the Byzantine Empire.
1278 – The naval Battle of Algeciras takes place in the context of the Spanish Reconquista resulting in a victory for the Emirate of Granada and the Maranid Dynasty over the Kingdom of Castile.
1467 – The Battle of Molinella: The first battle in Italy in which firearms are used extensively.
1536 – Sebastián de Belalcázar on his search of El Dorado founds 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 of France is crowned.
1554 – Mary I marries Philip II of Spain at Winchester Cathedral.
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 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.
1609 – The English ship Sea Venture, en route to Virginia, is deliberately driven ashore during a storm at Bermuda to prevent its sinking; the survivors go on to found a new colony there.
1693 – Ignacio de Maya founds the Real Santiago de las Sabinas, now known as Sabinas Hidalgo, Nuevo León, Mexico.
1722 – Dummer's War begins along the Maine-Massachusetts border.
1755 – British governor Charles Lawrence and the Nova Scotia Council order the deportation of the Acadians. Thousands of Acadians are sent to the British Colonies in America, France and England. Some later move to Louisiana, while others resettle in New Brunswick.
1759 – French and Indian War: In Western New York, British forces capture Fort Niagara from the French, who subsequently abandon Fort Rouillé.
1783 – American Revolutionary War: The war's last action, the Siege of Cuddalore, is ended by a preliminary peace agreement.
1788 – Wolfgang Amadeus Mozart completes his Symphony No. 40 in G minor (K550).
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 (Spain).
1799 – At Abu Qir 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; the Americans retreat to Fort Erie.
1824 – Costa Rica annexes Guanacaste from Nicaragua.
1837 – The first commercial use of an electrical telegraph is successfully demonstrated by William Cooke and Charles Wheatstone on July 25, 1837 between Euston and Camden Town in London.
1853 – Joaquin Murrieta, the famous Californio bandit known as "Robin Hood of El Dorado", is killed.
1861 – American Civil War: The United States Congress passes the Crittenden–Johnson Resolution, stating that the war is being fought to preserve the Union and not to end slavery.
1866 – The United States Congress passes legislation authorizing the rank of General of the Army. Lieutenant General Ulysses S. Grant becomes the first to be promoted to 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).
1893 – The Corinth Canal in the Gulf of Corinth, Greece is used for the first time.
1894 – The First Sino-Japanese War begins when the Japanese fire upon a Chinese warship.
1898 – The United States invasion of Puerto Rico begins with U.S. troops led by General Nelson Miles landing at harbor of Guánica, Puerto Rico.
1908 – Ajinomoto is founded. Kikunae Ikeda of the Tokyo Imperial University discovers that a key ingredient in kombu 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 from (Calais to Dover, England, United Kingdom) in 37 minutes.
1915 – RFC Captain Lanoe Hawker becomes the first British military aviator to earn the Victoria Cross, for defeating three German two-seat observation aircraft in one day, over the Western Front.
1917 – Sir Robert Borden introduces the first income tax in Canada as a "temporary" measure (lowest bracket is 4% and highest is 25%).
1920 – France captures Damascus.
1925 – Telegraph Agency of the Soviet Union (TASS) is established.
1934 – The Nazis assassinate Austrian Chancellor Engelbert Dollfuss in a failed coup attempt.
1940 – General Henri Guisan orders the Swiss Army to resist German invasion and makes surrender illegal.
1942 – Norwegian Manifesto calls for nonviolent resistance to the Nazis.
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 the First Canadian Army during the war: One thousand five hundred casualties, including 500 killed.
1946 – Operation Crossroads: An atomic bomb is detonated underwater in the lagoon of Bikini Atoll.
1946 – At Club 500 in Atlantic City, New Jersey, Dean Martin and Jerry Lewis stage their first show as a comedy team.
1952 – The U.S. non-incorporated territory of Puerto Rico adopts a constitution.
1956 – Forty-five 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.
1957 – The Republic of Tunisia is proclaimed.
1958 – The African Regroupment Party (PRA) holds its first congress in Cotonou.
1959 – SR.N1 hovercraft crosses the English Channel from Calais, France to Dover, England in just over two hours.
1959 – Lloyd J. Old introduced BCG, a tuberculosis vaccine, into experimental cancer research as a way to stimulate non-specific resistance to tumor growth. BCG was FDA-approved in 1991 and is now widely used as a first line treatment for superficial bladder cancer.
1961 – In a speech John F. Kennedy emphasizes that any attack on Berlin is an attack on NATO.
1965 – Bob Dylan goes electric as he plugs in at the Newport Folk Festival, signaling a major change in folk and rock music.
1969 – Vietnam War: U.S. 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 is the start of the "Vietnamization" of the war.
1973 – Soviet Mars 5 space probe is launched.
1976 – Viking program: Viking 1 takes the famous Face on Mars photo.
1978 – Puerto Rico police assassinate two nationalists in the Cerro Maravilla murders.
1978 – Louise Brown, the world's first "test tube baby" is born.
1979 – Another section of the Sinai Peninsula is peacefully returned by Israel to Egypt.
1983 – Black July: Thirty-seven Tamil political prisoners at the Welikada high security prison in Colombo are massacred by the fellow Sinhalese prisoners.
1984 – Salyut 7 cosmonaut Svetlana Savitskaya becomes the first woman to perform a space walk.
1992 – Opening ceremony of 1992 Summer Olympics
1993 – Israel launches a massive attack against Lebanon in what the Israelis call Operation Accountability, and the Lebanese call the Seven-Day War.
1993 – The Saint James Church massacre occurs in Kenilworth, Cape Town, South Africa.
1994 – Israel and Jordan sign the Washington Declaration, that formally ends the state of war that had existed between the nations since 1948.
1995 – A gas bottle explodes in Saint Michel station of line B of the RER (Paris regional train network). Eight are killed and 80 wounded.
1996 – In a military coup in Burundi, Pierre Buyoya deposes Sylvestre Ntibantunganya.
2000 – Concorde Air France Flight 4590 crashes at Paris Charles de Gaulle airport, killing 113 passengers.
2002 – A.P.J. Abdul Kalam became the 11th president of India.
2007 – Pratibha Patil is sworn in as India's first female president.
2010 – WikiLeaks publishes classified documents about the War in Afghanistan, one of the largest leaks in U.S. military history.
