My birth date is March 21st, the first day of the astrological year. It's frequently the date of the vernal equinox (or the autumnal equinox, if you're in the Southern Hemisphere).
Let's see, now. Three each, events, births, deaths, and observances ...
1871, Journalist Henry Morton Stanley set out to find missionary-explorer David Livingstone, who didn't know he was being looked for.
1918, Beginning of the Second Battle of the Somme. It's hard enough to believe they did it once.
1952, Alan Freed presented the Moondog Coronation Ball, the first ever rock and roll concert, in Cleveland, Ohio.
1685, Johann Sebastian Bach
1806, Benito Juarez
1943, Viv Stanshall
1556, Thomas Cranmer was burned at the stake. He made a good death, though Latimer got off the better line.
1487, Saint Nicholas of Flue, patron saint of Switzerland, dead of natural causes on his 70th birthday. He laid the foundations for Swiss neutrality and for the humanitarian treatment of prisoners of war, was a married layman with ten children, and is venerated by Catholics and Protestants alike.
1958, Futurian and SF author Cyril M. Kornbluth died of a heart attack after shoveling snow, then running to catch a commuter train. He was thirty-five.
1. Everyone's vernal equinox celebrations, which in some cases -- f.i. astrologers, Iranians, and followers of the Bahá'í faith -- means it's also their New Year observance. In theory, probably also means that any number of gods, goddesses, and other mythical personages were either born, died, or experienced significant events on this date.
2. Day of Googoo Expressions of Fuzzy Benevolence: Earth Day, International Day for the Elimination of Racial Discrimination, World Poetry Day, etc.
3. Feast of Saint Serapion the Scholastic, also known as Sarapion of Thmuis, a fourth-century Egyptian monk. He took part in all the best flame wars of his era, hung out with SS. Anthony and Athanasius, and was admired by Jerome, which should tell you something. Had it in for Manichaeanism, Macedonianism, and Arianism, the last of which got him banished by Constantius II. If Credo were an RPG, lots of characters would be named Serapion.