On this day: 25 April

The Abbasid army won a decisive victory over the forces of rebelling Armenian princes at the Battle of Bagrevand.

Pope Leo III was attacked by partisans of his predecessor Adrian I, but was rescued and taken to Charlemagne, as described in the epic Karolus magnus et Leo papa.

Eighty Years' War: The Dutch fleet destroys the anchored Spanish fleet at Gibraltar.

French composer Claude Joseph Rouget de Lisle wrote "La Marseillaise", now the national anthem of France.

Dano-Swedish War of 1808–1809: The Battle of Trangen takes place at Trangen in Flisa, Hedemarkens Amt, between Swedish and Norwegian troops.

Thornton Affair: Open conflict begins over the disputed border of Texas, triggering the Mexican–American War.

American Civil War: Forces under U.S. Admiral David Farragut demand the surrender of the Confederate city of New Orleans, Louisiana.

French and Vietnamese troops clash in Tonkin, when Commandant Henri Rivière seizes the citadel of Hanoi with a small force of marine infantry.

Spanish–American War: The United States Congress declares that a state of war between the U.S. and Spain has existed since April 21, when an American naval blockade of the Spanish colony of Cuba began.

At the San Remo conference, the principal Allies of World War I passed a resolution allocating League of Nations mandates for the administration of former Ottoman territories in the Middle East.

U.S. Supreme Court delivers its opinion in Erie Railroad Co. v. Tompkins and overturns a century of federal common law.

The United Negro College Fund is incorporated.

World War II: The last German troops retreat from Finnish soil in Lapland, ending the Lapland War. Military actions of the Second World War end in Finland.

United Nations Conference on International Organization: Founding negotiations for the United Nations begin in San Francisco.

World War II: Liberation Day (Italy): The National Liberation Committee for Northern Italy calls for a general uprising against the German occupation and the Italian Social Republic.

Korean War: Assaulting Chinese forces are forced to withdraw after heavy fighting with UN forces, primarily made up of Australian and Canadian troops, at the Battle of Kapyong.

The first practical solar cell is publicly demonstrated by Bell Telephone Laboratories.

The Saint Lawrence Seaway, linking the North American Great Lakes and the Atlantic Ocean, officially opens to shipping.

The U.S. Navy submarine Triton completed the first submerged circumnavigation of the world.

Robert Noyce is granted a patent for an integrated circuit.

Vietnam War: Nguyen Hue Offensive: The North Vietnamese 320th Division forces 5,000 South Vietnamese troops to retreat and traps about 2,500 others northwest of Kontum.

Carnation Revolution: A leftist military coup in Portugal overthrows the authoritarian-conservative Estado Novo regime.

More than 100 workers are exposed to radiation during repairs of at the Tsuruga Nuclear Power Plant in Japan.

Israel completes its withdrawal from the Sinai Peninsula per the Camp David Accords.

Cold War: American schoolgirl Samantha Smith is invited to visit the Soviet Union by its leader Yuri Andropov after he read her letter in which she expressed fears about nuclear war.

Mswati III (pictured) was crowned King of Swaziland, succeeding his father Sobhuza II.

Violeta Chamorro took office as President of Nicaragua, becoming the first female head of state in the Americas to have been elected in her own right.

Bulgaria and Romania sign the Treaty of Accession 2005 to join the European Union.

Boris Yeltsin's funeral: The first to be sanctioned by the Russian Orthodox Church for a head of state since the funeral of Emperor Alexander III in 1894.

Daniel Chong is discovered in a holding room in San Diego, having been incarcerated for five days without food or water.

A water crisis began when officials in Flint, Michigan, switched the city's water supply to the Flint River, leading to contamination.