The year 1066 is the 66th year in the 11th century according to the Christian era.
Succession struggle in England
January 4 – King Edward the Confessor dies childless. Harold Godwinson, Earl of Wessex, Harald III, King of Norway and William the Conqueror, Duke of Normandy all claim to be Edward's rightful successor.
January 5 – The Witan proclaim Harold king. He is crowned at Westminster Abbey
April - Halley's Comet is seen, and considered an (unfavorable) omen.
September 20 – Battle of Fulford: Harald, supported by Harold's brother Tostig, defeats Edward of Mercia and Morcar of Northumbria.
September 25 – Battle of Stamford Bridge: Harold defeats Harald and Tostig.
September 28 – William lands on the coast of England at Pevensey.
October 14 – Battle of Hastings: William defeats Harold.
October – The Witan elect Edgar Ætheling as king.
William advances to London to claim the throne, but is stopped by the population at London Bridge.
December - The still uncrowned Edgar surrenders to Willem.
December 25 – William is crowned King of England at Westminster Abbey.
December 30 – Granada Massacre: Joseph ibn Naghrela, the Jewish vizir of the Zirides, and many other Jews in Granada are murdered. First pogrom in Europe.
After Stenkil's death, both his son Erik VII and Erik VIII claim the crown, and they fight each other.
Rogier van Hainaut becomes bishop of Châlons-en-Champagne.
Henry IV of Germany marries Bertha of Savoy.
Mentioned for the first time: Alken, Ezemaal, Hoeselt, Izegem, Marke, Šibenik, Vlamertinge
Brittany - Conan II succeeded by his sister Havise
Champagne en Meaux - Odo II succeeded by his uncle Theobald III of Blois
England - Edward the Confessor succeeded by Harold II (Harold Godwinson), succeeded in turn by Edgar Ætheling (uncrowned), succeeded in turn by William the Conqueror
Norway - Harald III succeeded by his son Magnus II
Vendôme - Fulk succeeded by his son Burchard III under the tutelage of his nephew Guy of Nouatre
February 22 – Lý Nhân Tông, Emperor of Vietnam (1072-1127)
Henry of Burgundy, Count of Portugal (1096-1112)
January 4 - Edward the Confessor (~61), King of England (1042-1066)
June 1 – Conrad of Pfullingen, Archbishop of Trier (1066)
June 30 - Theobaldus of Provins (~32), French monk and saint
September 25 - Harald III (~51), King of Norway (1047-1066)
September 25 - Tostig Godwinson, Earl of Northumbria
October 14 - Harold II (~46), King of England (1066)
November 21 – Fulk, Count of Vendôme (1028-1032, 1056-1066)
December 11 - Conan II (~36), Duke of Brittany (1040-1066)
Ansverus, German abbot
Ariald of Como, Italian Church Reformer and Martyr
Stenkil, King of Sweden (ca. 1060-1066)
Elisabeth of Kiev, wife of Harald III of Norway (approximate date)