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421 BC

year

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionSep 8, 2026
Entity authorityQ233245
Source-derived summary

Year 421 BC was a year of the pre-Julian Roman calendar. At the time, it was known in Rome as the Year of the Consulship of Vibulanus and Barbatus (or, less frequently, year 333 Ab urbe condita). The denomination 421 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Events

By place

Greece

Nicias, the leader of the aristocratic and peace party in Athens and Pleistoanax, King of Sparta, negotiate the Peace of Nicias between Athens and Sparta, which brings a temporary end to the Peloponnesian War. The essence of the Peace of Nicias is a return to the antebellum period with most wartime gains being returned. Seventeen representatives from each side swear an oath to uphold the treaty, which is meant to last for one generation (30 years: meaning they are not responsible for the next generation's decision). All of Sparta's allies agree to sign the peace except for the Boeotians, Corinth, Elis, and Megara.

Alcibiades engineers an anti-Spartan alliance between Athens and the democracies of Argos, Mantinea and Elis.

Italy

The city of Cumae, the most northerly of the Greek colonies in Italy, falls to the Samnites.

By topic

Art

The construction of the Porch of the Maidens (the Caryatid Porch) commences at the Erechtheion which is part of the Acropolis in Athens.

Editorial summary

Begin with the source’s own compact description: “421 BC” is year. The dossier treats that line as a proposition to test through year, not as a finished interpretation.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current 233-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. For this dossier, year is the immediate research focus.
Editorial analysis

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.

Evidence profile

Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 8, 2026. The linked authority identifier is Q233245.

Critical limits

A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. 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.

Best used for
  • Subject orientation
  • Search vocabulary
  • Locating named sources
Verify next

The closest primary source, responsible institution and strongest cited specialist reference.

Three-step research path

  1. Establish the record: confirm the title “421 BC”, its source revision and the description used here.
  2. Expand the search: follow 421 BC primary sources, 421 BC archive and year research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

  1. Which source most directly establishes the central claim about “421 BC”?
  2. Which cited source is closest to the event, object or claim?
  3. What terminology or title could unlock a more precise catalogue search?
Subject index

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Source & attribution

This entry incorporates text from 421 BC” 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.