1075

1075 (MLXXV) was a common year starting on Thursday of the Julian calendar, the 1075th year of the Common Era (CE) and Anno Domini (AD) designations, the 75th year of the 2nd millennium, the 75th year of the 11th century, and the 6th year of the 1070s decade. As of the start of 1075, the Gregorian calendar was 6 days ahead of the Julian calendar, which was the dominant calendar of the time.

• February – Pope Gregory VII holds a council that publishes a decree against lay investiture.
• April – Pope Gregory VII publishes the Dictatus Papae (Sayings of the Pope, aka the Dictates of Hildebrand), in which he asserts papal authority over earthly as well as spiritual rulers.
• Revolt of the Earls: Three earls rebel against William I of England (William the Conqueror), in the last serious act of resistance to the Norman Conquest.
• First Battle of Langensalza: Henry IV, Holy Roman Emperor defeats the Saxon nobles and subjugates Saxony.
• The Liao Dynasty version of the Buddhist Tripitaka is completed (approximate date).
• Anund Gårdske is removed as king of Svealand and king Håkan the Red of Gothenland makes himself king of all Sweden.
• The Seljuk Turks take Jerusalem from the Fatimids.
• Lý dynasty forces under Lý Thường Kiệt defend Vietnam against invasion by Song Dynasty China.
• The Song Dynasty Chinese polymath scientist and statesman Shen Kuo solves a border dispute with the Liao Dynasty by finding old diplomatic records; he argues Emperor Daozong of Liao's bluffs point for point during a meeting at Mt. Yongan (near modern Pingquan in Hebei), and reestablishes the Song's borders.

• June 9 – Lothair II, Holy Roman Emperor (d. 1137)
• Saint Magnus Erlendsson (d. 1116 or 1117)
• Adelaide del Vasto (d. 1118)
• Orderic Vitalis, monk and historian (approximate date)

• June 10 – Ernest of Austria (b. 1027)
• August 2 – Patriarch John VIII of Constantinople
• December 4 – Anno II, archbishop of Cologne
• December 19 – Edith of Wessex, queen of Edward the Confessor of England
• John Xiphilinus, Byzantine historian
• Bleddyn ap Cynfyn, King of Gwynedd
• Peter Krešimir IV, King of Croatia