Wikipedia:Selected anniversaries/April 23
April 23: St George's Day in England, Portugal, Catalonia and Georgia; Passover begins at sunset (Judaism).
- 1014 - Irish forces led by Brian Boru clashed with the Vikings in the Battle of Clontarf.
- 1827 - Irish mathematician and physicist Rowan Hamilton presented his Theory of Systems of Rays.
- 1923 - Gdynia was inaugurated as a Polish seaport on the south coast of the Baltic Sea.
- 1954 - Hank Aaron of the Milwaukee Braves hit the first of his 755 home runs in Major League Baseball.
- 1982 - The Conch Republic "declared" independence from the United States.