On April 23:
- 1014 - Irish forces defeated Viking invaders in the Battle of Clontarf.
- 1348 - The founding of the Order of the Garter by Edward III was announced.
- 1597 - The Merry Wives of Windsor was first performed with Elizabeth I in attendance.
- 1933 - The Gestapo was established in Nazi Germany.
- 1994 - Physicists discovered the top quark subatomic particle.