|1057 by topic|
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|Births – Deaths|
|Establishments and disestablishments categories|
|Establishments – Disestablishments|
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- August 2 – Pope Stephen IX (sometimes referred to as Stephen X) succeeds Pope Victor II, as the 154th pope.
- August 3 - Frederik van Lotharingen elected as first Belgian Pope Stephen IX.
- August 15 – Battle of Lumphanan: Macbeth, King of Scotland, is killed by the future Malcolm III; Macbeth is succeeded as King of Scotland by his stepson Lulach, who is crowned at Scone, probably on September 8.
- August – Battle of Varaville: William the Conqueror defeats a Franco-Angevin army at the mouth of the Dives River, Normandy.
- Ferdinand I of Castile takes Lamego and Viseu, from Christian lords allied to the Muslim taifas.
- Reting Monastery is established by Dromtönpa north of Lhasa, as the seat of the Kadampa lineage.
- Jōchō, Japanese sculptor
- July 28 – Pope Victor II
- August 15 – King Macbeth of Scotland (b. 1005)
- Late August – Edward the Exile, son of Edmund II of England
- Ermesinde of Carcassonne, countess and regent of Barcelona (b. 972)
- Leofric, Earl of Mercia