March 21 events in history

537 Siege of Rome: King Vitiges attempts to assault the northern and eastern city walls, but is repulsed at the Praenestine Gate, known as the Vivarium, by the defenders under the Byzantine generals Bessas and Peranius
630 Emperor Heraclius returns the True Cross, one of the holiest Christian relics, to Jerusalem
717 Battle of Vincy between Charles Martel and Ragenfrid
1152 Annulment of the marriage of King Louis VII of France and Queen Eleanor of Aquitaine
1188 Emperor Antoku accedes to the throne of Japan
1413 Henry V becomes King of England
1556 In Oxford, Archbishop of Canterbury Thomas Cranmer is burned at the stake
1788 A fire in New Orleans leaves most of the town in ruins
1800 With the church leadership driven out of Rome during an armed conflict, Pius VII is crowned Pope in Venice with a temporary papal tiara made of papier-mâché
1801 The Battle of Alexandria is fought between British and French forces near the ruins of Nicopolis in Egypt
1804 Code Napoléon is adopted as French civil law
1814 Napoleonic Wars: Austrian forces repel French troops in the Battle of Arcis-sur-Aube
1821 Greek War of Independence: First revolutionary act in the monastery of Agia Lavra, Kalavryta
1844 The Bahá'í calendar begins. This is the first day of the first year of the Bahá'í calendar. It is annually celebrated by members of the Bahá'í Faith as the Bahá'í New Year or Náw-Rúz
1857 An earthquake in Tokyo, Japan kills over 100,000
1861 Alexander Stephens gives the Cornerstone Speech
1871 Otto von Bismarck is appointed Chancellor of the German Empire
1871 Journalist Henry Morton Stanley begins his trek to find the missionary and explorer David Livingstone
1913 Over 360 are killed and 20,000 homes destroyed in the Great Dayton Flood in Dayton, Ohio
1918 World War I: The first phase of the German Spring Offensive, Operation Michael, begins
1919 The Hungarian Soviet Republic is established becoming the first Communist government to be formed in Europe after the October Revolution in Russia
1921 The New Economic Policy is implemented by the Bolshevik Party in response to the economic failure as a result of War Communism
1925 The Butler Act prohibits the teaching of human evolution in Tennessee
1925 Syngman Rhee is removed from office after being impeached as the President of the Provisional Government of the Republic of Korea
1928 Charles Lindbergh is presented with the Medal of Honor for the first solo trans-Atlantic flight
1933 Construction of Dachau, the first Nazi concentration camp, is completed
1935 Shah of Iran Reza Shah Pahlavi formally asks the international community to call Persia by its native name, Iran, meaning "Land of the Aryans"
1937 Ponce Massacre: Nineteen people in Ponce, Puerto Rico, are gunned down by a police squad acting under orders of US-appointed Governor, Blanton C. Winship
1943 Wehrmacht officer Rudolf von Gersdorff plots to assassinate Adolf Hitler by using a suicide bomb, but the plan falls through. Von Gersdorff is able to defuse the bomb in time and avoid suspicion
1945 World War II: British troops liberate Mandalay, Burma
1945 World War II: Operation Carthage: Royal Air Force planes bomb Gestapo headquarters in Copenhagen, Denmark. They also hit a school and 125 civilians are killed
1945 World War II: Bulgaria and the Soviet Union successfully complete their defense of the north bank of the Drava River as the Battle of the Transdanubian Hills concludes
1946 The Los Angeles Rams sign Kenny Washington, making him the first African American player in the American football since 1933
1952 Alan Freed presents the Moondog Coronation Ball, the first rock and roll concert, in Cleveland, Ohio
1960 Apartheid in South Africa: Massacre in Sharpeville, South Africa: Police open fire on a group of unarmed black South African demonstrators, killing 69 and wounding 180
1963 Alcatraz, a federal penitentiary on an island in San Francisco Bay, closes
1965 Ranger program: NASA launches Ranger 9, the last in a series of unmanned lunar space probes
1965 Dr. Martin Luther King, Jr. leads 3,200 people on the start of the third and finally successful civil rights march from Selma to Montgomery, Alabama
1968 Battle of Karameh in Jordan between Israeli Defense Forces and Fatah
1970 The first Earth Day proclamation is issued by Mayor of San Francisco Joseph Alioto
1980 US President Jimmy Carter announces a United States boycott of the 1980 Summer Olympics in Moscow to protest the Soviet war in Afghanistan
1980 Dallas aired its "A House Divided" episode, which led to eight months of international intrigue regarding Who shot J.R
1986 Debi Thomas became the first African-American to win the World Figure Skating Championship
1989 Sports Illustrated reports allegations tying baseball player Pete Rose to baseball gambling
1990 Namibia becomes independent after 75 years of South African rule
1999 Bertrand Piccard and Brian Jones become the first to circumnavigate the Earth in a hot air balloon
2000 Pope John Paul II makes his first ever pontifical visit to Israel