On this day: 26 May

Germanicus celebrates a triumph in Rome for his victories over the Cherusci, Chatti, and other German tribes west of the Elbe.

Battle of Avarayr between Armenian rebels and the Sasanian Empire takes place. The Sasanids defeat the Armenians militarily but guarantee them freedom to openly practice Christianity.

Basil I is crowned as co-emperor of the Byzantine Empire by Michael III.

King Otto I elects his six-year-old son Otto II as heir apparent and co-ruler of the East Frankish Kingdom. He is crowned at Aachen, and placed under the tutelage of his grandmother Matilda.

Alfonso VII of León and Castile is crowned in León Cathedral as Imperator totius Hispaniae (Emperor of all of Spain).

The Battle of Haarlemmermeer, a naval engagement in the Eighty Years' War.

Portuguese Restoration War: Portuguese and Spanish forces both claimed victory at the Battle of Montijo.

A Great Jubilee Day held at North Stratford, Connecticut, celebrates the end of fighting in the American Revolutionary War.

Napoléon Bonaparte assumes the title of King of Italy and is crowned with the Iron Crown of Lombardy in Milan Cathedral, the gothic cathedral in Milan.

Establishment of the Peloponnesian Senate by the Greek rebels.

President Abraham Lincoln signs legislation organizing the Montana Territory.

American Civil War: General Edmund Kirby Smith negotiated the surrender of his army, the only significant Confederate Army force remaining in the war.

The impeachment trial of Andrew Johnson adjourned after the second and third articles of impeachment did not obtain enough votes from the U.S. Senate to convict.

Boston University is chartered by the Commonwealth of Massachusetts.

Germany's Emanuel Lasker defeated Wilhelm Steinitz to become the world chess champion, beginning a record 27-year reign.

Nicholas II is crowned as the last Tsar of Imperial Russia.

Charles Dow publishes the first edition of the Dow Jones Industrial Average.

Thousand Days' War: The Colombian Conservative Party turns the tide of war in their favor with victory against the Colombian Liberal Party in the Battle of Palonegro.

Românul de la Pind, the longest-running newspaper by and about Aromanians until World War II, is founded.

The Democratic Republic of Georgia is established.

The first 24 Hours of Le Mans is held in France. Run annually in June thereafter, it became the oldest endurance racing event in the world.

Abd el-Krim ends surrenders to the French, bringing an end to the Rif War.

The last Ford Model T rolls off the assembly line after a production run of 15,007,003 vehicles.

Walter Reuther and members of the United Auto Workers (UAW) clash with Ford Motor Company security guards at the River Rouge Complex in Dearborn, Michigan, during the Battle of the Overpass.

The House Un-American Activities Committee was established to investigate alleged disloyalty and subversive activities by people or organizations in the U.S. suspected of having communist or fascist ties.

World War II: The Battle of Gazala begins, in present-day Libya.

The U.S. Congress passes Public Law 80-557, which permanently establishes the Civil Air Patrol as an auxiliary of the United States Air Force.

H-dagurinn in Iceland: Traffic changes from driving on the left to driving on the right overnight.

Apollo program: Apollo 10 returns to Earth after a successful eight-day test of all the components needed for the forthcoming first crewed Moon landing.

The Soviet Tupolev Tu-144 becomes the first commercial transport to exceed Mach 2.

Cold War: The United States and the Soviet Union sign the Anti-Ballistic Missile Treaty.

The European Community adopts the European flag.

Zviad Gamsakhurdia becomes the first elected President of the Republic of Georgia in the post-Soviet era.

The Supreme Court of the United States rules in New Jersey v. New York that Ellis Island, the historic gateway for millions of immigrants, is mainly in the state of New Jersey, not New York.

The first "National Sorry Day" is held in Australia. Reconciliation events are held nationally, and attended by over a million people.

Narendra Modi takes oath as the 15th Prime Minister of India.