990

Events 
 January 1 – Kievan Rus' adopts the Julian calendar.
 Construction of the Al-Hakim Mosque begins in Cairo.
 The Pax Ecclesiae, an edict by the church in southern France attempting to outlaw acts of war against non-combatants and the clergy, is promulgated.

 Births 
 Conrad II, Holy Roman Emperor (approximate)
 Edmund II of England, (approximate)
 Mieszko II of Poland, king of Poland from 1025 to 1031, duke from 1032 to 1034.
 Yorimichi, regent to the Japanese emperor from 1017 to 1020 and from 1020 to 1068.
Johannes Skotus, Bishop of Mecklenburg (approximate)

 Deaths 
 Kaneie, regent to the Japanese emperor from 986 to 990.
 Al-Uqlidisi, Middle-East mathematician.
 Dunash ben Labrat