1017

By place

Europe

• Summer - Melus of Bari, a Lombard nobleman, revolts and is supported by Norman mercenaries at Capua. He marches into Apulia to catch the Byzantine army off-guard. Melus defeats the Byzantines on the banks of the Fortore River and ravages the territory in Apulia.
• Winter - Emperor Basil II replaces Leo Tornikios with the new catapan Basil Boioannes and sends him reinforcements from Constantinople.

  England

• January 6 - Cnut the Great is crowned king of England. In July he marries Emma of Normandy, the widow of Æthelred II. Cnut secures his ties with Normandy.
• Cnut the Great divides England into four earldoms: Wessex, Mercia, East Anglia and Northumbria.

  Arabian Empire

• Summer - Hamza ibn-'Ali ibn-Ahmad publicly declares the founding of the Druze religion, during the reign of the Fatimid Caliph Al-Hakim bi-Amr Allah.

  Africa

• The Sunnis of Kairouan revolt against the Shi'ite Zirid Dynasty. The city is quickly retaken and sacked.

  Asia

• Rajendra I, ruler of the Chola Dynasty, conquers Sri Lanka and annexes the island.

  By topic

Religion

• Construction of Saint Sophia's Cathedral in Kiev is started.