851
year
Year 851 (DCCCLI) was a common year starting on Thursday of the Julian calendar.
Events
By place
Asia
Bagrat II Bagratuni, Armenian prince and leader of a rebellion against the Abbasid Caliphate, is captured by the Abbasid army, and brought to the caliphal capital of Samarra.
Britain
Danish Viking raiders enter the Thames Estuary, and plunder Canterbury and London. They land at Wembury near Plymouth, but are defeated by Anglo-Saxon forces led by King Ethelwulf of Wessex. His eldest son Æthelstan of Kent, accompanied by Ealdorman Ealhhere, attacks a Viking fleet off the coast at Sandwich, and captures nine of the enemy vessels while the remainder flees.
China
Suleiman al-Tajir, Muslim merchant and traveller, visits China during the Tang Dynasty. He observes the manufacturing of Chinese porcelain at Guangzhou, and writes of his admiration for its transparent quality. Suleiman also describes the mosque at Guangzhou, its granaries, its local government administration, some of its written records, and the treatment of travellers, along with the use of ceramics, rice wine, and tea (approximate date).
Europe
August 22 – Battle of Jengland: Duke Erispoe takes command of the Breton forces after his father Nominoe, king of Brittany, dies. He continues an offensive against the Franks in alliance with Lambert II of Nantes.
Begin with the source’s own compact description: “851” is year. The dossier treats that line as a proposition to test through year, not as a finished interpretation.
Why this record matters
The phrase “year” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jan 3, 2025. The linked authority identifier is Q29966. None of the 0 selected statements returned an explicit reference.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “851”, its source revision and the description used here.
- Expand the search: follow 851 primary sources, 851 archive and year research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “851”?
- Which institution is responsible for the underlying evidence?
- Which cited source is closest to the event, object or claim?
Search terms from this dossier
This entry incorporates text from “851” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.