The source registry
Every source on this site is graded against the list below plus its declared type, and every event names its strongest source. This page is generated from the exact registry the grader runs on, so what you read here is what the code does.
How a source gets its grade
A source’s grade is the stronger of two signals: the domain it links to (matched against this registry) and the type its author declared (primary, journal, book, news, reference, or website). A journal article on a registry domain grades Peer-reviewed; the same claim on an unclassified personal site grades lower, no matter how it is typed. When a high grade rests on the author’s declared type rather than a registry match, the source is labeled (author-declared) wherever it appears: a first-hand account hosted on a personal site can honestly be primary testimony, but you deserve to know the grade came from the author, not the registry.
A domain missing from this registry is labeled unclassified source, which means exactly that: not yet classified. It is a statement about our list, not an accusation against the source. The registry is hand-maintained and grows as we cite new domains; suggest an addition if we are missing one.
Separately from grading, every source link is checked automatically: does it resolve, and does its content plausibly match the claim it is cited for. Those checks show on each event and in every timeline’s Source health panel.
Primary source
Archives of original documents and records. A link into these is treated as pointing at the historical record itself.
- loc.gov
- archives.gov
- nationalarchives.gov.uk
- avalon.law.yale.edu
- papersofthefounders.org
- founders.archives.gov
Peer-reviewed
Peer-reviewed journals and academic databases. Research that has been through formal review.
- nature.com
- science.org
- sciencedirect.com
- jstor.org
- doi.org
- pubmed.ncbi.nlm.nih.gov
- ncbi.nlm.nih.gov
- springer.com
- link.springer.com
- cambridge.org
- academic.oup.com
- pnas.org
- journals.plos.org
- ieee.org
Reputable source
Institutions, museums, official archives, and long-standing editorial press with named staff and standards. Any .edu or .gov domain also grades here automatically.
- britannica.com
- nasa.gov
- si.edu
- smithsonianmag.com
- unesco.org
- who.int
- noaa.gov
- usgs.gov
- esa.int
- cern.ch
- nps.gov
- metmuseum.org
- britishmuseum.org
- archive.org
- worldbank.org
- un.org
- ushmm.org
- iwm.org.uk
- nationalww2museum.org
- rafmuseum.org.uk
- nam.ac.uk
- worldhistory.org
- history.navy.mil
- history.army.mil
- nationalchurchillmuseum.org
- computerhistory.org
- museivaticani.va
- chateauversailles.fr
- mountvernon.org
- marinersmuseum.org
- museumofplay.org
- tate.org.uk
- thehenryford.org
- nationalmotormuseum.org.uk
- armyhistory.org
- medievalists.net
- louvre.fr
- parliament.uk
- scienceandmediamuseum.org.uk
- federalreservehistory.org
- bankofengland.co.uk
- eastman.org
- home.cern
- ecb.europa.eu
- nobelprize.org
- kennedy-center.org
- riaa.com
- rockhall.com
- nationalgeographic.com
- npr.org
- pbs.org
- time.com
- billboard.com
- history.com
- gilderlehrman.org
- battlefields.org
- constitutioncenter.org
- fdrlibrary.org
- 911memorial.org
- kff.org
- voanews.com
- deremilitari.org
- uen.pressbooks.pub
- lindahall.org
- invent.org
- automotivehalloffame.org
- lean.org
- hagerty.com
- darpa.mil
- aa.com.tr
- rmg.co.uk
- heritage.nf.ca
- thecanadianencyclopedia.ca
- waitangitribunal.govt.nz
- sahistory.org.za
- sciencemuseum.org.uk
- edwardworthlibrary.ie
- doaks.org
- christianhistoryinstitute.org
- ethw.org
- gamedeveloper.com
- gamasutra.com
- ign.com
- eurogamer.net
- gamesindustry.biz
- nintendolife.com
- timeextension.com
- arxiv.org
- gamesradar.com
- pcgamer.com
- kotaku.com
- gameinformer.com
- polygon.com
Read more about the method on how trust works.