On this day: 8 April

Abbasid forces decisively defeated the Saffarid emir Ya'qub ibn Laith, forcing the latter to halt his advance into Iraq.

Roger II of Sicily is excommunicated by Innocent II for supporting Anacletus II as pope for seven years, even though Roger had already publicly recognized Innocent's claim to the papacy.

Manuel I Komnenos succeeds his father John II Komnenos as Byzantine Emperor.

Mongol–Jin War: The Mongols begin their siege on Kaifeng, the capital of the Jin dynasty.

Seventh Crusade: Ayyubids of Egypt capture King Louis IX of France in the Battle of Fariskur.

Crusades: The Knights Hospitaller surrendered the Krak des Chevaliers, a castle in present-day Syria, to the army of the Mamluk sultan Baybars.

The city of Oulu, Finland, is founded by Charles IX of Sweden.

Kiliaen van Rensselaer purchased land near present-day Albany, New York, to establish Rensselaerswyck, which became the most successful patroonship under the Dutch West India Company.

Shearith Israel, the first synagogue in continental North America, is dedicated.

Czar Alexander I, the Russian Emperor and the Grand Duke of Finland, officially announces the transfer of the status of the Finnish capital from Turku to Helsinki.

Black Hawk War: Around 300 United States 6th Infantry troops leave St. Louis, Missouri to fight the Sauk Native Americans.

American Civil War: Late-arriving reinforcements helped Confederate forces rout the Union Army at the Battle of Mansfield.

Austro-Prussian War: Italy and Prussia sign a secret alliance against the Austrian Empire.

In Pollock v. Farmers' Loan & Trust Co. the Supreme Court of the United States declares unapportioned income tax to be unconstitutional.

Longacre Square in Midtown Manhattan was renamed Times Square after the New York Times building.

American cartoonist Winsor McCay released the silent short film Little Nemo (featured), one of the earliest animated films.

The Australian state of Western Australia voted to secede from the federation, but efforts to implement the result proved to be unsuccessful.

The Central Committee of the Mongolian People's Revolutionary Party elects Yumjaagiin Tsedenbal as General Secretary, marking the beginning of his 44-year-long tenure as de facto leader of Mongolia.

World War II: The United States Army Air Forces flew its first mission from India over the Hump (the eastern end of the Himalayas) to deliver materiel to China.

A team of computer scientists and others met to discuss the creation of a common business-oriented programming language, which became COBOL.

The Organization of American States drafts an agreement to create the Inter-American Development Bank.

A team of computer manufacturers, users, and university people led by Grace Hopper meets to discuss the creation of a new programming language that would be called COBOL.

The Netherlands and West Germany sign an agreement to negotiate the return of German land annexed by the Dutch in return for 280 million German marks as Wiedergutmachung.

The Progress Party was founded in a movie theater in Oslo, Norway.

Hank Aaron passes Babe Ruth as the all-time leader in career home runs by hitting his 715th home run off of Al Downing at Atlanta-Fulton County Stadium.

Voyageurs National Park is established by the U.S. Congress.

The conservative New Democracy party of Constantine Mitsotakis is elected in the Greek parliamentary election.

The Space Shuttle Discovery is launched on mission STS-56.

The Space Shuttle Atlantis is launched on mission STS-110, carrying the S0 truss to the International Space Station. Astronaut Jerry L. Ross also becomes the first person to fly on seven spaceflights.

A solar eclipse occurs, visible over areas of the Pacific Ocean and Latin American countries such as Costa Rica, Panama, Colombia and Venezuela.

On board Soyuz TMA-12, Yi So-yeon became the first Korean astronaut.

U.S. President Barack Obama and Russian President Dmitry Medvedev sign the New START Treaty.

Windows XP reaches its standard End Of Life and is no longer supported.

Bernie Sanders ends his presidential campaign, leaving Joe Biden as the Democratic Party's nominee.

Solar eclipse: A total solar eclipse takes place at the Moon's ascending node, visible across North America.