|Covid-19|April 18 or April 19 – Emperor Michael V of the Byzantine Empire attempts to remain sole emperor, by sending his adoptive mother and co-ruler Zoe of Byzantium to a monastery.
April 19 – Michael V of the Byzantine Empire is deposed by popular revolt. Zoe, Empress of the Byzantine Empire with co-rulers since 1028, becomes reigning empress with her sister Theodora.
June 8 – Edward the Confessor becomes King of England.
June 11 – Empress Zoe marries for the third time, and elevates her husband to the throne as Constantine IX.
George Maniaces, Byzantine general in Sicily, revolts against Constantine IX.
Harald III of Norway, at this time leader of the Varangian Guard in the Byzantine Empire, returns to Norway, possibly because of his involvement in Maniaces' revolt.
Magnus I of Norway becomes King of Denmark.
The Normans in Italy move their capital to Melfi.
Abad II succeeds his father to the throne of Sevilla.
Incursions by the Western Xia, and the threat of further Liao Dynasty military actions against the Song Dynasty, force an increase in tribute payments to the Liao.
The Almoravids, led by Abdullah Ibn Yasin, invade Morocco.
Byzantine-Arab Wars: The Byzantines conquer Edessa, returning it to Christian hands, after 400 years of Islamic rule.
Vladimir of Novgorod wages a campaign against the Tavastians (yem).
Pope Urban II (d. 1099)
June 8 – Harthacnut, King of Denmark and England
August 24 – Michael V, Byzantine Emperor (b. 1015)
Year 1042 (MXLII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar.
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