1623Centuries: 16th century - 17th century - 18th century
- August 6 - Pope Urban VIII is elected to the Papacy.
- Mustafa I becomes Ottoman Emperor succeeding Osman II, but is then succeeded by Murat IV.
- The Safavids recapture Baghdad.
- England first colonizes Saint Kitts and Nevis.
- Wilhelm Schickard invents his "Calculating Clock", and early mechanical calculator.
- Procopius's long-lost Secret History is rediscovered in the Vatican Library.
- Giambattista Marini publishes his long poem Adone.
- Tommaso Campanella publishes The City of the Sun.
- Johannes Rudbeck founds Rudbeckianska Gymnasiet, first gymnasium in Sweden.
- The Avedis Zildjian Company begins making cymbals at Constantinople.
- Second Thanksgiving celebrated at Plymouth Plantation.
- Erotomania is first mentioned in a psychiatric treatise.
- June 19 - Blaise Pascal, French mathematician, physicist and religious philosopher
- August 5 - Marc Antonio Cesti, composer (+ 1669)
- Margaret Cavendish, Duchess of Newcastle (+ 1673)
- Empress Meisho of Japan