1145

Events 
 February 15 — Pietro Bernardo Paganelli of Montemagno, Calci is elected as Pope Eugene III, and succeeds Pope Lucius II as the 167th pope.
 Pope Eugene III issues Quantum praedecessores, calling for the Second Crusade
 Construction begins on Notre-Dame d'Chartres in Chartres, France
 Kim Pusik and his team of historians finishes the making of the Korean historical text Samguk Sagi.
 Woburn Abbey founded.
 Arnold of Brescia joins the revolutionary Commune of Rome, where he becomes its leader for the next 10 years.

 Births 
 Maria of Antioch, Byzantine Empress (d. 1182)
 Marie de Champagne, Countess of Champagne (d. 1198)
 Theodora Comnena, Queen of Jerusalem 
 Pope Gregory IX (d. 1241) 
 Al-Adil I, Ayyubid-Egyptian general and ruler (d. 1218)
 Amalric II of Jerusalem (d. 1205)

 Deaths 
 February 15 — Pope Lucius II
 Zhang Zeduan, Chinese painter (b. 1085)