- 1618 2nd Defenestration of Prague; beginning of 30 Years War. Two Catholic Lords Regent and their secretary thrown out of window - they were not seriously injured by the 70 foot fall.
- 1785 Benjamin Franklin announces his invention of bifocals
- 1813 South American independence leader Simón Bolívar enters Mérida, leading the invasion of Venezuela, and is proclaimed El Libertador ("The Liberator")
- 1958 Mao Zedong starts "Great leap forward" movement in China
- 1998 The Good Friday Agreement is accepted in a referendum in Northern Ireland with 75% voting yes.
Canada's North West Mounted Police Force forms (it didn't get the "Royal" until 1904)
On May 23, 1873