Events on March 21 45
Year 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.
Year 630
Emperor Heraclius returns the True Cross, one of the holiest Christian relics, to Jerusalem.
Year 1152
Annulment of the marriage of King Louis VII of France and Queen Eleanor of Aquitaine.
Year 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.
Year 1801
The Battle of Alexandria is fought between British and French forces near the ruins of Nicopolis in Egypt.
Year 1814
Napoleonic Wars: Austrian forces repel French troops in the Battle of Arcis-sur-Aube.
Year 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.
Year 1871
Journalist Henry Morton Stanley begins his trek to find the missionary and explorer David Livingstone.
Year 1913
Over 360 are killed and 20,000 homes destroyed in the Great Dayton Flood in Dayton, Ohio.
Year 1918
World War I: The first phase of the German Spring Offensive, Operation Michael, begins.
Year 1919
The Hungarian Soviet Republic is established becoming the first Communist government to be formed in Europe after the October Revolution in Russia.
Year 1921
The New Economic Policy is implemented by the Bolshevik Party in response to the economic failure as a result of war communism.
Year 1925
Syngman Rhee is removed from office after being impeached as the President of the Provisional Government of the Republic of Korea.
Year 1928
Charles Lindbergh is presented with the Medal of Honor for the first solo trans-Atlantic flight.
Year 1935
Shah of Iran Reza Shah Pahlavi formally asks the international community to call Persia by its native name, Iran.
Year 1937
Ponce massacre: Nineteen people in Ponce, Puerto Rico are gunned down by police acting on orders of the US-appointed Governor, Blanton C. Winship.
Year 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.
Year 1945
World War II: Operation Carthage: Royal Air Force planes bomb Gestapo headquarters in Copenhagen, Denmark. They also accidentally hit a school, killing 125 civilians.
Year 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.
Year 1946
The Los Angeles Rams sign Kenny Washington, making him the first African American player in the American football since 1933.
Year 1952
Alan Freed presents the Moondog Coronation Ball, the first rock and roll concert, in Cleveland, Ohio.
Year 1960
Apartheid: Sharpeville massacre, South Africa: Police open fire on a group of unarmed black South African demonstrators, killing 69 and wounding 180.
Year 1965
Ranger program: NASA launches Ranger 9, the last in a series of unmanned lunar space probes.
Year 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.
Year 1968
Battle of Karameh in Jordan between the Israel Defense Forces and the combined forces of the Jordanian Armed Forces and PLO.
Year 1970
The first Earth Day proclamation is issued by Joseph Alioto, Mayor of San Francisco.
Year 1980
US President Jimmy Carter announces a United States boycott of the 1980 Summer Olympics in Moscow to protest the Soviet war in Afghanistan.
Year 1983
The first cases of the 1983 West Bank fainting epidemic begin; Israelis and Palestinians accuse each other of poison gas, but the cause is later determined mostly to be psychosomatic.
Year 1986
Debi Thomas became the first African American to win the World Figure Skating Championships
Year 1999
Bertrand Piccard and Brian Jones become the first to circumnavigate the Earth in a hot air balloon.
Year 2009
Four police officers are shot and killed and a fifth is wounded in two shootings at Oakland, California.