May 1 events in history

305 Diocletian and Maximian retire from the office of Roman Emperor
524 King Sigismund of Burgundy is executed at Orléans after an 8-year reign and is succeeded by his brother Godomar
880 The Nea Ekklesia is inaugurated in Constantinople, setting the model for all later cross-in-square Orthodox churches
1328 Wars of Scottish Independence end: By the Treaty of Edinburgh–Northampton the Kingdom of England recognises the Kingdom of Scotland as an independent state
1455 Battle of Arkinholm, Royal forces end the Black Douglas hegemony in Scotland
1576 Stephen Báthory, the reigning Prince of Transylvania, marries Anna Jagiellon and they become co-rulers of the Polish–Lithuanian Commonwealth
1707 The Act of Union joins the Kingdom of England and Kingdom of Scotland to form the Kingdom of Great Britain
1753 Publication of Species Plantarum by Linnaeus, and the formal start date of plant taxonomy adopted by the International Code of Botanical Nomenclature
1759 Josiah Wedgwood founds the Wedgwood pottery company in Great Britain
1776 Establishment of the Illuminati in Ingolstadt (Upper Bavaria), by Jesuit-taught Adam Weishaupt
1778 American Revolution: The Battle of Crooked Billet begins in Hatboro, Pennsylvania
1785 Kamehameha I, the king of Hawaiʻi, defeats Kalanikūpule and establishes the Kingdom of Hawaiʻi
1786 In Vienna, Austria, Mozart's opera The Marriage of Figaro is performed for the first time
1794 War of the Pyrenees: The Battle of Boulou ends, in which French forces defeat the Spanish and regain nearly all the land they lost to Spain in 1793
1840 The Penny Black, the first official adhesive postage stamp, is issued in the United Kingdom
1844 Hong Kong Police Force, the world's second modern police force and Asia's first, is established
1846 The few remaining Mormons left in Nauvoo, Illinois, formally dedicate the Nauvoo Temple
1851 Queen Victoria opens the Great Exhibition in London
1852 The Philippine peso is introduced into circulation
1856 The Province of Isabela was created in the Philippines in honor of the Queen Isabela II of Spain
1862 American Civil War: The Union Army completes its capture of New Orleans
1863 American Civil War: The Battle of Chancellorsville begins
1865 The Empire of Brazil, Argentina, and Uruguay sign the Treaty of the Triple Alliance
1866 The Memphis Race Riots begin. In three days time, 46 blacks and two whites were killed. Reports of the atrocities influenced passage of the Fourteenth Amendment to the United States Constitution
1869 The Folies Bergère opens in Paris
1875 Alexandra Palace reopens after being burned down in a fire in 1873
1884 Proclamation of the demand for eight-hour workday in the United States
1884 Moses Fleetwood Walker becomes the first black person to play in a professional baseball game in the United States
1885 The original Chicago Board of Trade Building opens for business
1886 Rallies are held throughout the United States demanding the eight-hour work day, culminating in the Haymarket affair in Chicago, in commemoration of which May 1 is celebrated as International Workers' Day in many countries
1893 The World's Columbian Exposition opens in Chicago
1894 Coxey's Army, the first significant American protest march, arrives in Washington, D.C
1898 Spanish–American War — Battle of Manila Bay: The United States Navy destroys the Spanish Pacific fleet in the first battle of the war
1900 The Scofield Mine disaster kills over 200 men in Scofield, Utah in what is to date the fifth-worst mining accident in United States history
1901 The Pan-American Exposition opens in Buffalo, New York
1915 The RMS Lusitania departs from New York City on her two hundred and second, and final, crossing of the North Atlantic. Six days later, the ship is torpedoed off the coast of Ireland with the loss of 1,198 lives
1925 The All-China Federation of Trade Unions is officially founded. Today it is the largest trade union in the world, with 134 million members
1925 The first Ritual of the Calling of an Engineer is held at the University of Toronto, Canada
1927 The first cooked meals on a scheduled flight are introduced on an Imperial Airways flight from London to Paris
1927 The Union Labor Life Insurance Company is founded by the American Federation of Labor
1930 The dwarf planet Pluto is officially named
1931 The Empire State Building is dedicated in New York City
1933 The Humanist Manifesto I published
1933 The Roca–Runciman Treaty between Argentina and Great Britain is signed by Julio Argentino Roca, Jr., and Sir Walter Runciman
1940 The 1940 Summer Olympics are cancelled due to war
1941 World War II: German forces launch a major attack on Tobruk
1944 World War II: Two hundred Communist prisoners are shot by the Germans at Kaisariani in Athens, Greece in reprisal for the killing of General Franz Krech by partisans at Molaoi
1945 World War II: A German newsreader officially announces that Adolf Hitler has "fallen at his command post in the Reich Chancellery fighting to the last breath against Bolshevism and for Germany". The Soviet flag is raised over the Reich Chancellery, by order of Stalin
1945 World War II: Nazi propaganda minister Joseph Goebbels and his wife Magda commit suicide in the Reich Garden outside the Führerbunker. Their children are also killed by having cyanide pills inserted into their mouths by their mother, Magda
1945 World War II: Yugoslav Partisans free Trieste