May 23: Victoria Day in Canada (2011)
- 1618 – In the Second Defenestration of Prague, Protestant members of the Bohemian aristocracy threw Catholic regents of Emperor Ferdinand II out the third-storey window of Prague Castle, precipitating the Thirty Years’ War.
- 1701 – Scottish privateer William Kidd was executed for piracy.
- 1844 – Siyyid `Alí-Muhammad Shírází proclaimed that he was “the Báb”, after a Shi`a religious concept, marking the beginning of the Bábí movement, the forerunner of the Bahá’í Faith.
- 1934 – American criminals Bonnie Parker and Clyde Barrow were ambushed and killed by police on a desolate road near their hideout in Bienville Parish, Louisiana.
- 1945 – End of World War II in Europe: Reichspräsident Karl Dönitz was captured and his Flensburg Government was dissolved.
- 2008 – To resolve a 29-year-old territorial dispute, the International Court of Justice awarded Middle Rocks to Malaysia and Pedra Branca to Singapore.