Millennium:	1st millennium
Centuries:	8th century 9th century 10th century
Decades:	830s 840s 850s 860s 870s
Years:	854 855 856 857 858 859 860

857 by topic
Leaders
Political entities State leaders Religious leaders
Categories
Births Deaths Establishments

857 in various calendars
Gregorian calendar	857 DCCCLVII
Ab urbe condita	1610
Armenian calendar	306 ԹՎ ՅԶ
Assyrian calendar	5607
Balinese saka calendar	778–779
Bengali calendar	264
Berber calendar	1807
Buddhist calendar	1401
Burmese calendar	219
Byzantine calendar	6365–6366
Chinese calendar	丙子年 (Fire Rat) 3554 or 3347 — to — 丁丑年 (Fire Ox) 3555 or 3348
Coptic calendar	573–574
Discordian calendar	2023
Ethiopian calendar	849–850
Hebrew calendar	4617–4618
Hindu calendars
- Vikram Samvat	913–914
- Shaka Samvat	778–779
- Kali Yuga	3957–3958
Holocene calendar	10857
Iranian calendar	235–236
Islamic calendar	242–243
Japanese calendar	Saikō 4 / Ten'an 1 (天安元年)
Javanese calendar	754–755
Julian calendar	857 DCCCLVII
Korean calendar	3190
Minguo calendar	1055 before ROC 民前1055年
Nanakshahi calendar	−611
Seleucid era	1168/1169 AG
Thai solar calendar	1399–1400
Tibetan calendar	阳火鼠年 (male Fire-Rat) 983 or 602 or −170 — to — 阴火牛年 (female Fire-Ox) 984 or 603 or −169

Year 857 (DCCCLVII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar.

Events

Emperor Michael III, under the influence of his uncle Bardas, banishes his mother Theodora to the Gastria Monastery. Bardas, the de facto regent, becomes the most powerful person in the Byzantine Empire.^[1]

November – Erispoe, ruler (duke) of Brittany, is assassinated by his cousin Salomon and followers, in the church at Talensac. King Charles the Bald acknowledges Salomon as the rightful 'king' of Brittany.
A Danish Viking fleet raids the cities of Dorestad, Paris and Orléans. Others sail up the Oise River, ravaging Beauvais and the abbey of Saint-Germer-de-Fly (approximate date).
Viking chieftain Rorik, with the agreement of King Lothair II, leaves Dorestad with a fleet and forces his rival Horik II to recognise him as ruler over Denmark (approximate date).

The first recorded major outbreak of ergotism kills thousands of people in the Rhine Valley. They have eaten bread made from rye infected with the ergot fungus parasite Claviceps purpurea (approximate date).

Births