840

This article is about the year 840. For the number, see 840 (number).

Millennium:	1st millennium
Centuries:	8th century – 9th century – 10th century
Decades:	810s  820s  830s  – 840s –  850s  860s  870s
Years:	837 838 839 – 840 – 841 842 843

840 by topic

Politics

State leaders – Sovereign states

Birth and death categories

Births – Deaths

Establishment and disestablishment categories

Establishments – Disestablishments

840 in other calendars

Gregorian calendar	840 DCCCXL
Ab urbe condita	1593
Armenian calendar	289 ԹՎ ՄՁԹ
Assyrian calendar	5590
Bengali calendar	247
Berber calendar	1790
Buddhist calendar	1384
Burmese calendar	202
Byzantine calendar	6348–6349
Chinese calendar	己未年 (Earth Goat) 3536 or 3476     — to — 庚申年 (Metal Monkey) 3537 or 3477
Coptic calendar	556–557
Discordian calendar	2006
Ethiopian calendar	832–833
Hebrew calendar	4600–4601
Hindu calendars
- Vikram Samvat	896–897
- Shaka Samvat	762–763
- Kali Yuga	3941–3942
Holocene calendar	10840
Iranian calendar	218–219
Islamic calendar	225–226
Japanese calendar	Jōwa 7 (承和７年)
Julian calendar	840 DCCCXL
Korean calendar	3173
Minguo calendar	1072 before ROC 民前1072年
Seleucid era	1151/1152 AG
Thai solar calendar	1382–1383

Emperor Lothair I (795–855)

Year 840 (DCCCXL) was a leap year starting on Thursday (link will display the full calendar) of the Julian calendar.

Events

By Place

Europe

• June 20 – Emperor Louis the Pious falls ill and dies at his hunting lodge on an island in the Rhine near his imperial palace at 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. The 17-year-old Charles the Bald becomes king of the Franks and joins the fight with his half-brother Louis the German in resisting Lothair.

Britain

• King Wigstan of Mercia, grandson of former ruler Wiglaf (see 839), declines his kingship and prefers the religious life. He asks his widowed mother, princess Ælfflæd to act as regent. A nobleman of the line of the late king 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. He is buried at Repton Abbey and later revered as a saint. The Mercian throne is seized by Berhtric's father, Beorhtwulf.
• Vikings make pernament settlements with their first 'wintering over' located at Lough Neagh in Northern Ireland (approximate date).

Asia

• Emperor Wen Zong (Li Ang) dies after a 13-year reign in which he has failed to break the power of his palace eunuchs. He is succeeded by his brother Wu Zong as Chinese ruler of the Tang Dynasty.
• The Yenisei Kirghiz settled along the Yenisei River, sack with a force of around 80,000 horsemen the Uyghur capital, Ordu-Baliq. Driving the Uyghurs out of Mongolia. End of the Uyghur Khaganate.

By topic

Religion

• Nobis becomes bishop of St. David's in the Welsh Kingdom of Dyfed (approximate date).

Births

• Abu al-Hassan al-Nuri, Muslim sufi (approximate date)
• Clement of Ohrid, Bulgarian scholar (approximate date)
• Eudokia Ingerina, Byzantine empress (approximate date)
• January 19 – Michael III, Byzantine emperor (d. 867)
• Notker the Stammerer, Benedictine monk (approximate date)
• Richardis, Frankish empress (approximate date)
• Sunyer II, Frankish nobleman (approximate date)
• Theodard, archbishop of Narbonne (approximate date)
• Theodore II, pope of the Catholic Church (d. 897)
• Unruoch III, margrave of Friuli (approximate date)
• Ya'qub ibn al-Layth, founder of the Saffarid Dynasty (d. 879)

Deaths

• Agobard, archbishop of Lyon (b. 779)
• Ansovinus, archbishop of Camerino
• Czimislav, king of the Sorbs (approximate date)
• March 14 – Einhard, Frankish scholar
• Hilduin, archbishop of Paris (b. 775)
• Li Chengmei, prince of the Tang Dynasty
• June 20 – Louis the Pious, king of the Franks (b. 778)
• June 11 – Junna, emperor of Japan (b. 785)
• June 16 – Rorgon I, Frankish nobleman (or 839)
• Wen Zong, emperor of the Tang Dynasty (b. 809)
• Wigstan, king of Mercia (approximate date)