What happened on May 1 ?

305 - Diocletian and Maximian retire from the office of Roman Emperor.

1045 - Gregory VI appointed Pope.

1328 - Wars of Scottish Independence end: Treaty of Edinburgh-Northampton ? England recognises Scotland as an independent nation.

1576 - Stefan Batory, the reigning Prince of Transylvania, married Anna Jagiellon and became the co-rulers of the Polish-Lithuanian Commonwealth.

1707 - The Act of Union joins England and Scotland to form the Kingdom of Great Britain.

1751 - The first cricket match is played in America.

1753 - Publication of Species Plantarum by Linnaeus, and the formal start date of plant taxonomy adopted by the International Code of Botanical Nomenclature.

1786 - Opening night of the opera The Marriage of Figaro by Wolfgang Amadeus Mozart in Vienna.

1834 - The British colonies abolish slavery.

1851 - The Great Exhibition is opened in London by Queen Victoria.

1863 - American Civil War: The Battle of Chancellorsville begins.

1869 - The Folies Bergères open in Paris.

1884 - Proclamation of the demand for eight-hour workday in the United States

1886 - The start of the general strike which eventually wins the eight-hour workday in the United States. These events are today commemorated as May Day or Labor Day in most industrialized countries.

1893 - The World's Columbian Exposition opens in Chicago, Illinois.

1894 - Coxey's Army, the first significant American protest march, arrives in Washington D.C..

1898 - Spanish-American War: The 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 200 in Scofield, Utah in the now fifth-worst mining accident in United States history.

1901 - The Pan-American Exposition opens in Buffalo, New York.

1915 - RMS Lusitania departs New York City on her 202nd & final crossing of the North Atlantic. Six days later she'll be torpedoed off the Irish coast with the loss of 1,198 lives.

1925 - The All-China Federation of Trade Unions is official founded. Today it is the largest trade union in the world, with 134 million members.

1927 - The first cooked meals on a scheduled flight are introduced on an Imperial Airways flight from London to Paris.

1930 - The planet Pluto is officially named.

1931 - The Empire State Building is dedicated in New York City.

1940 - The 1940 Summer Olympics are cancelled due to war.

1941 - Orson Welles's Citizen Kane premieres in New York City

1941 - World War II: German forces launch a major attack on Tobruk.

1945 - Soviet troops raise the Soviet Flag over the Reichstag, in Berlin

1946 - Start of 3 year Pilbara strike of Indigenous Australians.

1948 - The Democratic People's Republic of Korea (North Korea) is established, with Kim Il Sung as president.

1950 - Guam is organized as a United States commonwealth.

1956 - The polio vaccine developed by Jonas Salk is made available to the public.

1960 - Cold War: U-2 Crisis ? Francis Gary Powers, in a Lockheed U-2 spyplane, is shot down over the Soviet Union, sparking off a diplomatic crisis.

1971 - Amtrak (the National Railroad Passenger Corporation) is formed to take over U.S. passenger rail service.

1978 - Japan's Naomi Uemura, travelling by dog sled, becomes the first person to reach the North Pole alone.

1978 - The first unsolicited bulk commercial e-mail (which would later become known as "spam") was sent by a DEC marketing representative to every ARPANET address on the west coast of the United States.

1978 - May Day Bank Holiday introduced across England.

1982 - The 1982 World's Fair opens in Knoxville, Tennessee.

1989 - The coat of arms of Greenland was adopted.

1997 - Terry Burrows breaks the world record for speed window-cleaning, completing three 45-inch square windows in 18.46 seconds.

2003 - 2003 invasion of Iraq: In what becomes known as the "Mission Accomplished" speech, President George W. Bush declares "major combat operations in Iraq have ended" on board USS Abraham Lincoln off the coast of California.

2004 - Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, and Slovenia join the European Union, celebrated at the residence of the Irish President in Dublin.

2006 - Immigrants and their supporters across the United States carry out the Great American Boycott, a one day national protest against the enforcement of pending immigration laws criminalizing illegal immigrants and those who aid them, and calling for amnesty to be given to those in the U.S..

2006 - The Puerto Rican government ran out of money and had to force the closure of schools and all other government agencies.