Epoch
reference point from which time is measured
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided by congruity, or by following conventions understood from the epoch in question. The epoch moment or date is usually defined from a specific, clear event of change, an epoch event. Where a historical shift is gradual, the epoch is defined as the precise moment a critical threshold is crossed.
Calendar eras
Pre-modern eras
Anno Mundi [lit. "Year of the World"] (years since the creation of the world) is used in
the Byzantine calendar (5509 BC).
the Hebrew calendar (3761 BC).
The Mesoamerican Long Count Calendar uses the creation of the fourth world in 3114 BC.
Olympiads, the ancient Greek era of four-year periods between Olympic Games, beginning in 776 BC.
Ab urbe condita ("from the foundation of the city"), used to some extent by Roman calendars of the Roman imperial period (753 BC).
Buddhist calendars tend to use the epoch of 544 BC (date of Buddha's parinirvana).
“Epoch” enters the record as reference point from which time is measured. Crown Archives preserves that source wording while asking what Epoch, point and time can confirm, complicate or overturn.
Why this record matters
“Epoch” is worth following because a concise public description often conceals a longer documentary argument. Here, Epoch, point and time provides the most credible route into that argument.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 19, 2026. The linked authority identifier is Q507810. 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 “Epoch”, its source revision and the description used here.
- Expand the search: follow Epoch primary sources, Epoch archive and Epoch 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 “Epoch”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Epoch” 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.