1047 (MXLVII) was a common year starting on Thursday of the Julian calendar, the 1047th year of the Common Era (CE) and Anno Domini (AD) designations, the 47th year of the 2nd millennium, the 47th year of the 11th century, and the 8th year of the 1040s decade. As of the start of 1047, the Gregorian calendar was 6 days ahead of the Julian calendar, which was the dominant calendar of the time.

• Battle of Val-ès-Dunes: William the Conqueror, with assistance from King Henry I of France, takes control of Normandy by defeating the rebel Norman barons at Caen.
• Harald III becomes sole king of Norway.
• Sweyn II is crowned king of Denmark.
• Pope Clement II is replaced by Pope Benedict IX as the 150th pope.
• Revolt of Leo Tornikios in the Byzantine Empire

• Hugh d'Avranches, 1st Earl of Chester, French born, English nobleman (died 1101)
• Judith of Swabia, daughter of Henry III, Holy Roman Emperor

• October 9 – Pope Clement II
• October 25 – King Magnus I of Norway (b. 1024)