Year 854 (DCCCLIV) was a common year starting on Monday (link will display the full calendar) of the Julian calendar.
|Ab urbe condita||1607|
|Balinese saka calendar||775–776|
|Chinese calendar||癸酉年 (Water Rooster)|
3550 or 3490
— to —
甲戌年 (Wood Dog)
3551 or 3491
|- Vikram Samvat||910–911|
|- Shaka Samvat||775–776|
|- Kali Yuga||3954–3955|
|Japanese calendar||Ninju 4 / Saikō 1|
|Minguo calendar||1058 before ROC|
|Seleucid era||1165/1166 AG|
|Thai solar calendar||1396–1397|
980 or 599 or −173
— to —
981 or 600 or −172
- Emperor Lothair I meets his (half) brothers (Louis the German and Charles the Bald) in Attigny, Ardennes for the third time, to continue the system of "con-fraternal government".
- Viking chieftains Rorik and Godfrid Haraldsson return to Denmark, to gain power after the death of King Horik I. During a civil war, they are forced to go back to Friesland.
- The German city of Ulm is first mentioned, in a document by Louis the German. 
- Croatian–Bulgarian battle: Bulgarian Khan (later Knyaz) Boris I, attacks the Duchy of Littoral Croatia, ruled by Duke Trpimir I during the First Croatian-Bulgarian War. It is fought on the Croatian territory in the vicinity of the Croatian–Bulgarian border in present-day northeastern Bosnia and Herzegovina. None of warring sides emerges victorious, Bulgarian forces retreat and finally both parties subsequently conclude a peace treaty.
- King Æthelwulf of Wessex sends his two youngest sons, Alfred and Æthelred, on a pilgrimage to Rome.
- King Æthelweard of East Anglia dies, and is succeeded by his 14-year-old son Edmund ("the Martyr").
- King Cyngen of Powys makes the first pilgrimage to Rome of a Welsh ruler.
- Viking chieftain Ubba winters in Milford Haven (Wales) with 23 ships.
- Eardulf becomes bishop of Lindisfarne, after the death of Eanbert.
- Al-Mu'tadid, Muslim caliph (or 861)
- Cadell ap Rhodri, king of Seisyllwg (d. 909)
- Cui Yin, chancellor of the Tang Dynasty (d. 904)
- Theobald the Elder, Frankish nobleman (d. 942)
- Abu Thawr, Muslim scholar (b. 764)
- Æthelweard, king of East Anglia
- Eanbert, bishop of Lindisfarne
- Horik I, Viking king of Denmark
- Luidger, bishop of Utrecht (approximate date)
- Osburh, queen of Wessex (approximate date)
- Sahnun ibn Sa'id, Muslim jurist (or 855)
- Túathal mac Máele-Brigte, king of Leinster
- Wang Yuankui, Chinese general (b. 812)
- Wigmund, archbishop of York
- ^ Norsemen in the Low Countries: Extracts from the Annales Bertiniani, 855 entry Archived June 14, 2011, at the Wayback Machine
- ^ Zeit.de: Das Alter der Städte
- ^ "Boris I". Encyclopædia Britannica, Inc. November 13, 2021.
- ^ Fine, John van Antwerp (November 13, 2021). The Early Medieval Balkans, page 112. The University of Michigan Press, 1983. ISBN 978-0472081493.
- ^ Deliso, Christopher (November 13, 2021). The History of Croatia and Slovenia, page 46. ABC-CLIO, LLC, 2020, Santa Barbara, California. ISBN 9781440873232.
- ^ ASC 854 - English translation at Project Gutenberg
- ^ Kirby, The Earliest English Kings, p. 161.
- ^ Milford Haven Town Council website History, Chronology of Events Archived March 13, 2012, at the Wayback Machine