Editing 840 (section)

== Events ==
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===By place===

==== Europe ====
* [[June 20]] &ndash; Emperor [[Louis the Pious]] falls ill and dies at his [[Jagdschloss|hunting lodge]], on an island in the [[Rhine]], near his [[Imperial Palace Ingelheim|imperial palace]] at [[Ingelheim am Rhein|Ingelheim]], while suppressing a revolt. His eldest son [[Lothair I]] succeeds him as [[Holy Roman Emperor]], and tries to seize all the territories of the late [[Charlemagne]]. [[Charles the Bald]], 17, becomes king of the [[Francia|Franks]], and joins with his half-brother [[Louis the German]], in resisting Lothair. 
* [[Vikings]] from [[Norway]] capture [[Dublin]], and establish a Norse kingdom in [[Ireland]].

==== Britain ====
* King [[Wigstan|Wigstan of Mercia]], grandson of former ruler [[Wiglaf of Mercia|Wiglaf]] (see [[839]]), declines his kingship in preference of the religious life. He asks his widowed mother, Princess [[Ælfflæd of Mercia (II)|Ælfflæd]], to act as [[regent]]. A [[Nobility|nobleman]] of the line of the late king [[Beornred of Mercia|Beornred]], named Berhtric, wishes to marry her but he is a relative. Wigstan refuses the match, and is murdered by followers of Berhtric at [[Wistow, Leicestershire|Wistow]]. He is buried at [[Repton Abbey]], and later revered as a [[saint]]. The [[Mercia]]n throne is seized by Berhtric's father, [[Beorhtwulf of Mercia|Beorhtwulf]].<ref>Zaluckyj & Zaluckyj, "Decline"</ref>{{rp|238–239}}
* [[Vikings]] make permanent settlements with their first '[[Overwintering|wintering over]]', located at [[Lough Neagh]] in [[Northern Ireland]] (approximate date).

==== Asia ====
* Emperor [[Emperor Wenzong of Tang|Wenzong]] (Li Ang) dies after a 13-year reign, in which he has failed to break the power of his palace [[eunuch]]s. He is succeeded by his brother [[Emperor Wuzong of Tang|Wu Zong]], as Chinese ruler of the [[Tang dynasty]].
* The [[Yenisei Kirghiz]] settle along the [[Yenisei River]], and sack with a force of around 80,000 horsemen the Uyghur capital, [[Ordu-Baliq]] (driving the [[Uyghurs]] out of [[Mongolia]]). This ends  the [[Uyghur Khaganate]].<ref name="ca">[http://www.britannica.com/EBchecked/topic/102315/history-of-Central-Asia/73536/Reunification#73538 History of Central Asia].</ref>
*The [[840 Erzurum earthquake]] takes place in the city of Qaliqala (modern [[Erzurum]]).<ref name="Guidoboni">Guidoboni, Traina, 1995, p. 121</ref>

=== By topic ===

==== Religion ====
* [[Nobis (bishop)|Nobis]] becomes [[bishop]] of [[Diocese of St David's|St. David's]], in the Welsh [[Kingdom of Dyfed]] (approximate date). 
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