- 1252 Pope Innocent IV issues the papal bull ad exstirpanda, which authorizes, but also limits, the torture of heretics in the Medieval Inquisition.
- 1618 Johannes Kepler discovers harmonics law
- 1730 Robert Walpole becomes effectively Britain's 1st prime minister (was: chief min)
- 1869 National Woman Suffrage Association forms in New York, founded by Susan B. Anthony and Elizabeth Cady Stanton
- 1940 McDonald's opens its first restaurant in San Bernardino, California.
- 1951 AT&T becomes the 1st US corporation to have a million stockholders after young car salesman Brady Denton purchases 7 shares worth $1,078
- 1988 USSR begins withdrawing its 115,000 troops from Afghanistan
Mickey Mouse made his 1st ever appearance in silent film "Plane Crazy"
On May 15, 1928