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
Bahá'í calendar	-1004–-1003
Bengali calendar	247
Berber calendar	1790
English Regnal year	N/A
Buddhist calendar	1384
Burmese calendar	202
Byzantine calendar	6348–6349
Chinese calendar	己未年十一月廿三日 (3476/3536-11-23) — to — 庚申年十二月初四日 (3477/3537-12-4)
Coptic calendar	556–557
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
Igbo calendar
- Ǹrí Ìgbò	-160–-159
Iranian calendar	218–219
Islamic calendar	225–226
Japanese calendar
Juche calendar	N/A (before 1912)
Julian calendar	840    DCCCXL
Korean calendar	3173
Minguo calendar	1072 before ROC 民前1072年
Thai solar calendar	1383

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

Events

By Place

Europe

• After the death of Louis the Pious, his sons Lothar, Charles the Bald and Louis the German fight over the division of the Holy Roman Empire, with Lothar succeeding as Emperor.

Asia

• Tang Wu Zong succeeds Tang Wen Zong as emperor of China.
• Kyrgyz in Yenisey region (north) defeat Uyghurs. End of the Uyghur khaganate.

Births

• January 19—Michael III, Byzantine Emperor
• Abu Al-Husayn Al-Nuri, early Sufi
• Ya'qub-i Laith Saffari, founder of the Saffarid Dynasty in Sistan
• Notker the Stammerer, Benedictine monk at the Abbey of Saint Gall
• Eudokia Ingerina, wife of Byzantine emperor Basil I
• Richardis. Holy Roman Empress
• Clement of Ohrid, Bulgarian scholar, writer and pan-Slavic saint
• Sunyer II, Count of Empúries and Roussillon
• Theodard, Archbishop of Narbonne
• Unruoch III of Friuli, Margrave of Friuli

Deaths

• June 20—Louis the Pious, King of the Franks, Emperor of the Holy Roman Empire (b. 778)
• Emperor Junna of Japan (b. 786)
• Emperor Wenzong of Tang