Skip to content
This is an official ODERSA website.Here's how you know

The official domain

The address of this site ends in odersa.org. Every service the association runs sits on a subdomain of odersa.org and nowhere else. If the address in your browser's address bar does not end in odersa.org, this site is not ours.

Free, and no account

Everything is open straight away. No sign-up, no account, no password, no subscription, no advertising. Nothing is held back for those who pay, because there is nothing to pay for.

No data collected

This site does not follow you: no tracker, no tracking cookie, no measurement tool built into these pages, and nothing measured on your device. Our host counts requests in aggregate, as any server that answers does: a total, never a profile. You do not have to take our word for it: open your browser’s developer tools, go to the Network tab, and reload the page. You will see the full list of what the site asks for. Everything comes from odersa.org, nothing goes anywhere else.

Free to reuse

The content is published under the CC BY 4.0 licence. You may copy it, translate it, print it and pass it on, for your classes as much as for the people around you, on one condition only: credit ODERSA.

English
The LibraryODERSA publishing house
An ODERSA resource · Knowledge programmeA book only goes online once it is whole and read by someone else.

Chapter 15 of 16 · The great periods of history

Sources

Every document this book rests on, with its exact address and the date on which ODERSA consulted it.

What this chapter makes it possible to do

Every date, every figure and every quotation in this book goes back to one of the entries below. That is what makes the volume verifiable: a reader who doubts can open the document, read it, and see for themselves. What is not a dated fact but a line of reasoning can be recognised by its form, and the last section of this chapter says where the book reasons instead of reporting. A fact in this book that cannot be found again at its source is a mistake, and the volume's notice says how to report it.

Each entry carries four pieces of information. The document, with its title as it is written on its own page; the titles of the French documents and the names of the institutions are kept in French, because that is how they have to be searched for. The institution that publishes it. The exact address where it is to be found. And the date on which ODERSA opened and read it. That last one is not a formality: a page online changes, and an address that answered one day may not answer the next.

The appendix that precedes this chapter, the one on school correspondences, carries its own sources in the same format and for the same reason. All these sources are free of charge and open to everyone, with no account, no subscription and no particular software. It is a condition this house imposes on itself: a book whose evidence sits behind a toll can only be checked by those who can pay, and it then stops being a common good.

The official texts

These documents set the periodisation boundaries and the landmark dates this book takes up. They are published by the French state and can be consulted without restriction.

  1. Arrêté du 22 avril 2026 fixant les programmes d'enseignement d'éducation physique et sportive et d'histoire-géographie du cycle des apprentissages fondamentaux (cycle 2) et du cycle de consolidation (cycle 3). The title is reproduced as it is written on its own page, cycle names included: a shortened title cannot be found again. This is the text that brings into force the history syllabus quoted throughout this book.Légifrance, the French public service for the dissemination of law · consulted on August 9, 2026www.legifrance.gouv.fr/jorf/id/JORFTEXT000054048160
  2. Annexe 4 de cet arrêté : le programme d'histoire et de géographie. Source of the periodisation boundaries, of the landmark dates of Prehistory, of the sentence on the division of time as a convention, and of the definition of what a timeline is for.Ministère de l'Éducation nationale, Bulletin officiel n° 22 du 28 mai 2026 · consulted on August 9, 2026www.education.gouv.fr/sites/default/files/document/annexe-4-programme-d-histoire-geographie-cycle-3-516779.pdf
  3. Déclaration du 26 août 1789 des droits de l'homme et du citoyen. Published among the texts of national law in force. Source of the date and of the quotation from the first article.Légifrance, the French public service for the dissemination of law · consulted on August 9, 2026www.legifrance.gouv.fr/contenu/menu/droit-national-en-vigueur/constitution/declaration-des-droits-de-l-homme-et-du-citoyen-de-1789

The scientific and heritage institutions

These pages supply the explanations of method: measuring time, dating, excavating. They are written by the bodies that practise these methods themselves.

  1. Chronologie, Ères et Calendriers. Source of the length of the tropical year, of the Gregorian reform of 1582, of the rule for secular leap years, of the shift of the Julian calendar and of the adoption of the reform country by country.Institut de mécanique céleste et de calcul des éphémérides, Observatoire de Paris · consulted on August 9, 2026promenade.imcce.fr/fr/pages2/277.html
  2. Carbone 14. Source of the atmospheric origin of carbon 14, of what happens at the death of an organism, of the half-life of 5,730 years and of the detection limit close to fifty thousand years.Laboratoire de mesure du carbone 14, run jointly by several French public bodies · consulted on August 9, 2026lmc14.lsce.ipsl.fr/carbone-14.html
  3. La datation du carbone 14 avec ARTEMIS. Source of the description of the French accelerator mass spectrometry facility, commissioned in 2004, and of its annual analysis capacity.Ministère de la Culture, the French ministry of culture · consulted on August 9, 2026www.culture.gouv.fr/thematiques/sciences-du-patrimoine/thematiques-de-recherche/etude-des-materiaux/La-datation-du-carbone-14-avec-ARTEMIS
  4. La stratigraphie. Source of the definition of the stratigraphic approach, of its statement in the seventeenth century by Nicolas Sténon, and of the example of the stone tools dated by the depth at which they were buried in the 1840s.Institut national de recherches archéologiques préventives · consulted on August 9, 2026www.inrap.fr/magazine/histoire-de-larcheologie/lapport-du-terrain/la-stratigraphie
  5. Datation des figures de Lascaux. Source of the complete sequence of datings proposed since 1940, of the carbon 14 and then accelerator measurements, and of the sentence on the difficulties of establishing a precise diagnosis.Ministère de la Culture, collection des grands sites archéologiques · consulted on August 9, 2026archeologie.culture.gouv.fr/lascaux/fr/datation-figures-lascaux
  6. Âges conventionnels, âges calibrés : du bon usage des datations 14C. Source of the convention that fixes the present of datings at the year 1950, the date the method was invented.Ministère de la Culture, collection des grands sites archéologiques · consulted on August 10, 2026archeologie.culture.gouv.fr/lascaux/fr/ages-conventionnels-ages-calibres-du-bon-usage-des-datations-14c

The libraries and the original documents

These three entries give access to first-hand documents or to their scientific description. They are the ones that make it possible to check what a text from the past says exactly.

  1. Naissance, vie et mort du cunéiforme. Source of the dating of the invention of writing between 3500 and 3300 BCE, of its location in Lower Mesopotamia, of its administrative and urban cause, and of how long it was in use.Bibliothèque nationale de France, Les Essentiels · consulted on August 9, 2026essentiels.bnf.fr/fr/livres-et-ecritures/les-systemes-ecriture/4ab92041-e146-4582-b101-2d12bf3502b3-ecritures-en-mesopotamie/article/c510245e-aed6-4749-90e6-6cc397e659f6-naissance-vie-et-mort-cuneiforme
  2. Recueil de textes historiques (1449-1453/1454) ; Récit de la prise de Constantinople (1453) ; Chronique en vers (1244-1392). Digitised manuscript. Source of the account dated 28 May, of the notice that puts the taking of the city on 29 May, and of the description of the view of the siege.Bibliothèque nationale de France, Gallica · domaine public · consulted on August 9, 2026gallica.bnf.fr/ark:/12148/btv1b10720537g
  3. Séquence pédagogique consacrée à Christophe Colomb. Source of the existence and the accessibility of the logbook of the first voyage, and of the terrestrial globe made by Martin Behaim in 1492.Bibliothèque nationale de France · consulted on August 9, 2026multimedia-ext.bnf.fr/pdf/SP-Colomb.pdf

On the form of this book

These two documents explain why the timelines in this volume are written as tables rather than drawn, and why a table that scrolls inside its own area is a correct form and not a defect.

  1. Complex Images. Source of the rule of the two descriptions for a complex image, and of the wording according to which a long description is presented as headings, text and a table.World Wide Web Consortium, Web Accessibility Initiative · consulted on August 9, 2026www.w3.org/WAI/tutorials/images/complex
  2. Understanding Success Criterion 1.4.10: Reflow. Source of the named exemption enjoyed by data tables, cited in the chapter on reading a timeline: a wide table is allowed to scroll, provided it does so inside its own area and does not carry the page with it.World Wide Web Consortium, Web Accessibility Initiative · consulted on August 9, 2026www.w3.org/WAI/WCAG22/Understanding/reflow.html

What ODERSA set aside, and why

A book that has set nothing aside has read nothing. Several documents consulted while preparing this volume do not appear in it, and the reasons fall into three families.

The first reason is the toll. Articles in history journals and commercial encyclopaedias deal precisely with periodisation and with its national character, sometimes better than what has been kept here. They are paid for or closed to reading. This house leans only on sources that a reader with no budget can open, which sets aside the best texts as much as the least good.

The second reason is authority. Popularising sites, blogs and collaborative encyclopaedias give the same dates as the documents kept, often with more detail. They are not cited, because a piece of information that does not go back to an institution answerable for what it publishes cannot be checked: it can only be copied.

The third reason is the silence of the source on what was being asked of it. Some institutional pages consulted did not say what we had hoped to find in them. They were set aside rather than forced. A source cited for a statement it does not carry is worse than no source at all, because it looks like proof.

Three reservations this book owns

The first concerns the boundaries of the end of Antiquity. The official syllabus writes its four periodisation landmarks in an abbreviated form, and the line carrying the dates 395 and 476 does not read as sharply as the other three. This book has therefore kept the two dates and the fact they designate, without reproducing the abbreviated wording of the document. A reader who wants to decide for themselves will find the complete document at the address given above.

The second concerns durations. All the period durations given in this volume are approximate, and they are calculated from the boundaries kept, not taken from a source. The duration of Prehistory in particular depends entirely on where the beginning of humanity is placed, a question on which specialists do not agree and which this book does not settle. The shares in hundredths in the chapter on the great timeline are calculated by taking three hundred thousand years for Prehistory: they would change with another starting value, and the table says so in its caption.

The third concerns what this book REASONS instead of reporting. A few passages rest on no document in the list above, because they deduce instead of observing: what the name Middle Ages implies about whoever gave it, what the move to agriculture entails for those who live through it, what a blank on a timeline really measures. They are written so that the reader can redo the reasoning themselves, and they carry no figures. A line of reasoning is open to argument; it is not cited as a source, and this book never presents it as one.

An address that no longer answers is not a lost source. The institutions cited here keep their publications, and a page that has moved can be found again by searching for its exact title on the institution's site, as it is written in the entries above. That is also why each entry gives the title in full and not only the link.