26 May

17 – Germanicus returns to Rome as a conquering hero; he celebrates a triumph for his victories over the Cherusci, Chatti and other German tribes west of the Elbe.
451 – Battle of Avarayr between Armenian rebels and the Sassanid Empire takes place. The Empire defeats the Armenians militarily but guarantees them freedom to openly practice Christianity.
1135 – Alfonso VII of León and Castile is crowned in the Cathedral of Leon as Imperator totius Hispaniae, "Emperor of all of Spain".
1293 – An earthquake strikes Kamakura, Kanagawa, Japan, killing about 30,000.
1328 – William of Ockham, Franciscan Minister-General Michael of Cesena and two other Franciscan leaders secretly leave Avignon, fearing a death sentence from Pope John XXII.
1538 – Geneva expels John Calvin and his followers from the city. Calvin lives in exile in Strasbourg for the next three years.
1637 – Pequot War: A combined Protestant and Mohegan force under English Captain John Mason attacks a Pequot village in Connecticut, massacring approximately 500 Native Americans.
1647 – Alse Young, hanged in Hartford, Connecticut, becomes the first person executed as a witch in the British American colonies.
1736 – Battle of Ackia: British and Chickasaw soldiers repel a French and Choctaw attack on the Chickasaw village of Ackia, near present-day Tupelo, Mississippi. The French, under Louisiana governor Jean Baptiste Le Moyne, Sieur de Bienville, had sought to link Louisiana with Acadia and the other northern colonies of New France.
1770 – The Orlov Revolt, an attempt to revolt against the Ottoman Empire before the Greek War of Independence, ends in disaster for the Greeks.
1783 – A Great Jubilee Day held at North Stratford, Connecticut celebrated end of fighting in American Revolution.
1805 – Napoléon Bonaparte assumes the title of King of Italy and is crowned with the Iron Crown of Lombardy in the Duomo di Milano, the gothic cathedral in Milan.
1822 – 116 people die in the Grue Church fire, the biggest fire disaster in Norway's history.
1828 – Feral child Kaspar Hauser is discovered wandering the streets of Nuremberg.
1830 – The Indian Removal Act is passed by the U.S. Congress; it is signed into law by President Andrew Jackson two days later.
1857 – Dred Scott is emancipated by the Blow family, his original owners.
1864 – Montana is organized as a United States territory.
1865 – American Civil War: Confederate General Edmund Kirby Smith, commander of the Confederate Trans-Mississippi division, is the last general of the Confederate Army to surrender, at Galveston, Texas.
1868 – The impeachment trial of U.S. President Andrew Johnson ends with Johnson being found not guilty by one vote.
1869 – Boston University is chartered by the Commonwealth of Massachusetts.
1879 – Russia and the United Kingdom sign the Treaty of Gandamak establishing an Afghan state.
1896 – Nicholas II becomes Tsar of Russia.
1896 – Charles Dow publishes the first edition of the Dow Jones Industrial Average.
1897 – Dracula, a novel by Irish author Bram Stoker is published.
1906 – Vauxhall Bridge is opened in London.
1908 – At Masjed Soleyman (مسجد سليمان) in southwest Persia, the first major commercial oil strike in the Middle East is made. The rights to the resource are quickly acquired by the Anglo-Persian Oil Company.
1917 – Several powerful tornadoes rip through Illinois, including the city of Mattoon, killing 101 people and injuring 689.
1918 – The Democratic Republic of Georgia is established.
1936 – In the House of Commons of Northern Ireland, Tommy Henderson begins speaking on the Appropriation Bill. By the time he sits down in the early hours of the following morning, he had spoken for 10 hours.
1938 – In the United States, the House Un-American Activities Committee begins its first session.
1940 – World War II: Battle of Dunkirk – In France, Allied forces begin a massive evacuation from Dunkirk, France.
1942 – World War II: The Battle of Bir Hakeim takes place.
1948 – The U.S. Congress passes Public Law 557, which permanently establishes the Civil Air Patrol as an auxiliary of the United States Air Force.
1966 – British Guiana gains independence, becoming Guyana.
1969 – Apollo program: Apollo 10 returns to Earth after a successful eight-day test of all the components needed for the forthcoming first manned moon landing.
1970 – The Soviet Tupolev Tu-144 becomes the first commercial transport to exceed Mach 2.
1972 – Willandra National Park is established in Australia.
1972 – The United States and the Soviet Union sign the Anti-Ballistic Missile Treaty.
1977 – George Willig climbs the South Tower of New York City's World Trade Center.
1981 – Prime Minister of Italy Arnaldo Forlani and his coalition cabinet resign following a scandal over membership of the pseudo-masonic lodge P2 (Propaganda Due).
1983 – A strong 7.7 magnitude earthquake strikes Japan, triggering a tsunami that kills at least 104 people and injures thousands. Many people go missing and thousands of buildings are destroyed.
1986 – The European Community adopts the European flag.
1991 – Zviad Gamsakhurdia becomes the first elected President of the Republic of Georgia in the post-Soviet era.
1991 – Lauda Air Flight 004 crashes in rural Thailand, killing 223.
1992 – The blockade of Dubrovnik is broken. Following this, the siege of Dubrovnik ends in the next months.
1998 – The Supreme Court of the United States rules that Ellis Island, the historic gateway for millions of immigrants, is mainly in the state of New Jersey, not New York.
2004 – The United States Army veteran Terry Nichols is found guilty of 161 state murder charges for helping carry out the Oklahoma City bombing.
2008 – Severe flooding begins in eastern and southern China that will ultimately cause 148 deaths and force the evacuation of 1.3 million.

Holidays and observances

Christian Feast Day:
Augustine of Canterbury (Anglican Communion and Eastern Orthodox)
Lambert of Vence
Philip Neri
Quadratus of Athens
Zachary, Bishop of Vienne
May 26 (Eastern Orthodox liturgics)
Crown Prince's Birthday (Denmark)
Independence Day, commemorates the day of the First Republic in 1918. (Georgia)
Independence Day, celebrates the independence of Guyana from the United Kingdom in 1966.
Mother's Day (Poland)
National Day of Healing (Australia)