What happened on May 22 ?

1176 - Murder attempt by the Hashshashin (Assassins) on Saladin near Aleppo.

1377 - Pope Gregory XI issues five papal bulls to denounce the doctrines of English theologian John Wycliffe.

1455 - Wars of the Roses: At the First Battle of St Albans, Richard, Duke of York, defeats and captures King Henry VI of England.

1762 - Sweden and Prussia sign the Treaty of Hamburg.

1807 - A grand jury indicts former Vice President of the United States Aaron Burr on a charge of treason.

1819 - The SS Savannah leaves port at Savannah, Georgia, United States, on a voyage to become the first steamship to cross the Atlantic Ocean. The ship arrived at Liverpool, England on June 20.

1840 - The transporting of British convicts to the New South Wales colony is abolished.

1856 - Congressman Preston Brooks of South Carolina beats Senator Charles Sumner with a cane in the hall of the United States Senate for a speech Sumner had made attacking Southerners who sympathized with the pro-slavery violence in Kansas ("Bleeding Kansas").

1872 - Reconstruction: U.S. President Ulysses S. Grant signs the Amnesty Act of 1872 into law restoring full civil rights to all but about 500 Confederate sympathizers.

1906 - The 1906 Summer Olympics, not now recognized as part of the official Olympic Games, opens in Athens.

1906 - Wright brothers are granted U.S. patent number 821,393 for their "Flying-Machine".

1915 - Five trains collide in the Quintinshill rail crash near Gretna Green, Scotland, killing 227 people and injuring 246; the accident is found to be the result of non-standard operating practices during a shift change at a busy junction.

1936 - Aer Lingus (Aer Loingeas) is founded by the Irish government as the national airline of the Republic of Ireland.

1939 - World War II: Germany and Italy sign the Pact of Steel.

1942 - Mexico enters World War II on the side of the Allies.

1947 - Cold War: In an effort to fight the spread of Communism, U.S. President Harry S. Truman signs an act into law that will later be called the Truman Doctrine. The act grants $400 million in military and economic aid to Turkey and Greece.

1960 - An earthquake measuring 9.5 on the Richter scale, now known as the Great Chilean Earthquake, hits southern Chile. It is the most powerful earthquake ever recorded.

1962 - Continental Airlines Flight 11 crashes after bombs explode.

1964 - U.S. President Lyndon B. Johnson announces the goals of his Great Society social reforms to bring an "end to poverty and racial injustice" in America.

1967 - The Innovation department store in the centre of Brussels, Belgium, burns down. It is the most devastating fire in Belgian history, which results in 323 dead and missing and 150 injured.

1967 - Mister Rogers' Neighborhood, the longest-running children's series on U.S. television, airs its first episode.

1968 - The nuclear-powered submarine the USS Scorpion sinks with 99 men aboard 400 miles southwest of the Azores.

1969 - Apollo 10's lunar module flies within 8.4 nautical miles (16 km) of the moon's surface.

1972 - Ceylon adopts a new constitution, changes its name to Sri Lanka, and joins the Commonwealth of Nations.

1990 - North and South Yemen are unified to create the Republic of Yemen.

1990 - The Windows 3.0 operating system is released by Microsoft.

1992 - After 30 years, 66-year-old Johnny Carson hosts The Tonight Show for the last time.

1997 - Kelly Flinn, US Air Force's first female bomber pilot certified for combat, accepts a general discharge in order to avoid a court martial.

1998 - Lewinsky scandal: A federal judge rules that United States Secret Service agents can be compelled to testify before a grand jury concerning the scandal, involving President Bill Clinton.

2002 - In Washington, DC, the remains of the missing Chandra Levy are found in Rock Creek Park.

2002 - American civil rights movement: A jury in Birmingham, Alabama, convicts former Ku Klux Klan member Bobby Frank Cherry of the 1963 murders of four girls in the bombing of the 16th Street Baptist Church.

2003 - In Fort Worth, Texas, Annika Sörenstam becomes the first woman to play the PGA Tour in 58 years.

2004 - Felipe, Prince of Asturias, of the Spanish Royal Family marries Letizia Ortiz Rocasolano.

2004 - The U.S. town of Hallam, Nebraska, is wiped out by a powerful F4 tornado that broke a width record at an astounding 2.5 miles wide. It also killed one local resident.

2006 - Results from the Montenegrin independence referendum, 2006 are announced. 55.4% of voters voted to become independent from the Serbia and Montenegro Union.