1017

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 ("the Bulgar Slayer") replaces Leo Tornikios with the new catapan Basil Boioannes and sends him reinforcements (including a detachment of the elite Varangian Guard) from Constantinople.

England

• January 6 – Cnut ("the Great") is crowned king of England. In July he marries Emma of Normandy, the widow of Æthelred the Unready, securing his ties with Normandy.
• Cnut 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 (modern Tunisia) revolt against the Shi'ite Zirid dynasty. The city is quickly retaken and sacked.

Asia

• March – Fujiwara no Michinaga passes the title of regent of Japan (Sesshō) to his eldest son Fujiwara no Yorimichi.
• September
  • Prince Atsuakira of Japan, eldest son of ex-Emperor Sanjō, having been struck by a skin disease and under intense pressure from Michinaga, resigns the title of Crown Prince in favour of his younger brother, Prince Atsunaga who marries Fujiwara no Kanshi, daughter of Michinaga.
  • Michinaga makes a pilgrimage to the Iwashimizu Shrine in Japan accompanied by many courtiers. The travelers divide themselves amongst 15 boats for a floating trip down the Yotogawa River. One of the vessels overturns and more than 30 people lose their lives.
• December 24 – Michinaga is granted the honorary title Daijō-daijin of Japan.
• Rajendra I, ruler of the Chola dynasty (in modern India), conquers Sri Lanka and annexes the island.

By topic

Religion

• Construction of Saint Sophia Cathedral, Kyiv is started (approximate date).

• October 28 – Henry III, Holy Roman Emperor (d. 1056)
• Ahimaaz ben Paltiel, Italian-Jewish liturgical poet (d. 1060)
• Bermudo III (or Vermudo), king of León (approximate date)
• Floris I, count of Friesland west of the Vlie (approximate date)
• Ramanuja, Indian Sri Vaishnavism philosopher (d. 1137)
• Vikramabahu (Kassapa VI), king of Sri Lanka (d. 1041)
• Zhou Dunyi, Chinese philosopher and cosmologist (d. 1073)

• February 5 – Sancho García, count of Castile
• June 5 – Sanjō, ex-emperor of Japan (b. 976)
• June 22 – Leo Passianos, Byzantine general
• July 6 – Genshin, Japanese Tendai scholar (b. 942)
• September 18 – Henry of Schweinfurt, German nobleman
• October 6 – Wang Dan, Chinese Grand Chancellor
• Eadric Streona, ealdorman of Mercia
• Eadwig Ætheling, son of Æthelred II
• Elvira of Castile, queen consort of León
• Emnilda, duchess consort of Poland
• Fujiwara no Junshi, Japanese empress (b. 957)
• Judith of Brittany, duchess of Normandy (b. 982)
• Ma'mun II, Ma'munid ruler of Khwarezm
• Ramon Borrell, count of Barcelona (b. 972)
• Renaud of Vendôme, French nobleman