306 – Constantine I is proclaimed Roman emperor by his troops.
864 – The 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 declared after the Almoravids, led by Ali ibn Yusuf, are defeated by Prince Afonso Henriques. He then becomes Afonso I, King of Portugal, after calling the first assembly of the estates-general of Portugal at Lamego, where he is given the Crown from the Bishop of Bragança, to confirm the independence.
1261 – The city of Constantinople is recaptured by Nicaean forces under the command of Alexios Strategopoulos, re-establishing the Byzantine Empire.
1722 – The Three Years War begins along the Maine and Massachusetts border.
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 the French, who subsequently abandon Fort Rouillé.1797 – Horatio Nelson loses more than 300 men and his right arm during the failed conquest attempt of Tenerife (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; the Americans retreat to Fort Erie.1824 – Costa Rica annexes Guanacaste from Nicaragua.
Good for us! 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 (commonly called "5-star general"). Lieutenant General Ulysses S. Grant becomes the first to be promoted to this rank
1869 – The Japanese daimyō 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.
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 (The land invasion, proper, began that day: Sea-based bombardment and shelling of the capital city of San Juan had been occurring since May 1898).
1907 – Korea becomes a protectorate of Japan.
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.
1920 – France captures Damascus.
1934 – The Nazis assassinate Austrian Chancellor Engelbert Dollfuss in a failed coup attempt.1940 – General 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: 1,500 casualties, including 500 killed.
1946 – Operation Crossroads: an atomic bomb is detonated underwater in the lagoon of Bikini atoll.
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.
1961 – In a speech John F. Kennedy 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 is the start of the "Vietnamization" of the war.
1979 – Another section of the Sinai peacefully returned by Israel to Egypt.
1983 – Black July: 37 Tamil political prisoners at the Welikada high security prison in Colombo are massacred by the fellow Sinhalese prisoners.
1993 – Israel launches a massive attack against terrorist forces in Lebanon in what the Israelis call Operation Accountability, and the Lebanese call Seven-Day War.
1994 – Israel and Jordan sign the Washington Declaration, which formally ends the state of war that had existed between the nations since 1948.
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.