- January 11 — Theodora becomes reigning empress of the Byzantine Empire.
- April 13 — Pope Victor II succeeds Pope Leo IX as the 153rd pope.
- October 24 — Ralph the Timid is defeated by the Welsh.
- December 18 - The Seljuk Turks capture Baghdad; Al-Malik al-Rahim is taken prisoner.
- In Wales Gruffydd ap Llwelyn kills Gruffydd ap Rhydderch in battle and recaptures Deheubarth.
- Verditius Competition of 1055 is held at Verdi.