1181

Events 
 Jayavarman VII defeats the Cham and assumes control of the Khmer kingdom.
 The word Albigensians first used by chronicler Geoffroy du Breuil of Vigeois to describe the inhabitants of Albi, France.
 September 1 — Pope Lucius III succeeds Pope Alexander III as the 171st pope.
 Chinese and Japanese astronomers observe what has since come to be understood as a supernova. One of only eight supernovae in the Milky Way observed in recorded history, it appeared in the constellation Cassiopeia and was visible in the night sky for about 185 days. The radio source 3C58 is thought to be the remnant from this event.
 Beginning of the Yowa era in Japan. The era is marked by famine.

 Births 
 Saint Francis of Assisi, Italian founder of the Franciscan Order (died 1226)
 Saint Teresa of Portugal
 Jayavarman VII, king of the Khmer (died 1219)
 Deaths 
 January 30 — Emperor Takakura of Japan (b. 1161)
 March 17 — Henry I of Champagne
 June 30 — Hugh de Kevelioc, 3rd Earl of Chester, English politician (b. 1147)
 August 30 — Pope Alexander III (b. c. 1100–1105)
 Taira no Kiyomori, Japanese warlord (b. 1118)
 As-Salih Ismail al-Malik, ruler of Syria (b. 1163)