25 July

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 at Rome to commemorate Constantine's victory over Maxentius at the Milvian Bridge.
864 – The Edict of Pistres of Charles the Bald orders defensive measures against the Vikings.
1139 – Battle of Ourique: The Almoravids, led by Ali ibn Yusuf, are defeated by Prince Afonso Henriques.
1261 – The city of Constantinople is recaptured by Nicaean forces under the command of Alexios Strategopoulos, re-establishing the Byzantine Empire.
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 as 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, México.
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.
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.
1783 – American Revolutionary War: The war's last action, the Siege of Cuddalore, is ended by preliminary peace agreement.
1788 – Wolfgang 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 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.
1837 – The first commercial use of an electric telegraph is successfully demonstrated by William Cooke and Charles Wheatstone on 25 July 1837 between Euston and Camden Town in London.
1853 – Joaquin Murietta, 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 five-star 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 daimyō 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 – After over two months of sea-based bombardment, 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 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 from (Calais to Dover) 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 – Telecommunications: the first transatlantic two-way radio broadcast takes place.
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 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.
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 colonial territory of Puerto Rico adopts a constitution of local-limited powers, approved by the United States Congress in contravention of then-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.
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 to Dover in just over 2 hours.
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 launched.
1976 – Viking program: Viking 1 takes the famous Face on Mars photo.
1978 – The Cerro Maravilla incident occurs.
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: 37 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.
1993 – Israel launches a massive attack against Lebanon in what the Israelis call Operation Accountability, and the Lebanese call Seven-Day War.
1993 – The Saint 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 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 – 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 female president.
2010 – Wikileaks publishes classified documents about the War in Afghanistan, one of the largest leaks in U.S. military history.

Holidays and observances

Christian Feast Day:
Anne (Eastern Christianity)
Christopher (Western Christianity)
Cucuphas
James the Great (Western Christianity)
Julian of Le Mans (translation)
July 25 (Eastern Orthodox liturgics)
Commonwealth Constitution Day, formerly Occupation Day. (Puerto Rico)
Ebernoe Horn Fair (Sussex, southern England)
Furrinalia (Roman Empire)
Guanacaste Day (Costa Rica)
Inca festival in honor of the thunder god Ilyap'a
National Day of Galicia (Galicia)
Republic Day (Tunisia)