Chapter 1 of 16 · The great periods of history
About this book
What this volume does, what it does not do, in what order to read it, and to whom ODERSA owes the documents it rests on.
Why this volume exists
Nobody is born knowing that the Middle Ages come after Antiquity. That filing seems obvious to whoever has learnt it; it is obvious to nobody else. An adult going back to study, a child meeting a timeline for the first time, a teacher who has to explain why the past is cut into pieces: all of them run into the same difficulty. The past is continuous, and it is told in slices.
This volume does not tell history. It gives the frame in which a history is filed: the units that measure time, the timeline that puts them end to end, the five great periods of the French convention, the dates that serve as boundaries, and the means by which a date is established. It is made to be opened at the page you need, not to be read from one end to the other without stopping.
The matter of this book is visual. The tables, the facing columns and the summary cards carry the essentials; the text accompanies them and explains them. A timeline, here, is a table of dates. A diagram is a written sequence of steps. Nothing is drawn, and that takes nothing away: a relation between two facts can be written as well as traced, and it can then be read aloud, translated, copied out and enlarged without breaking.
The scope, said before we begin
What this book does
- It gives the units for measuring time, from the second to the millennium, and the way to write a century.
- It explains how a timeline is read, and what a timeline never shows.
- It sets out the five great periods of the French convention, with the dates that separate them.
- It gives a table of landmarks for each period, and it says where each landmark comes from.
- It shows how an object, a text or an excavation makes it possible to establish a date.
- It names the most common dating methods and says what each one can and cannot do.
What it does not do
- It does not tell the events of each period: that would be five other books.
- It does not deal with the history of any one country, nor with daily life in a given age.
- It does not give the complete list of dates that a teaching syllabus asks for.
- It does not present the French division as the only one possible, nor as the best one.
- It does not teach how to handle the instruments of a dating laboratory.
- It does not replace reading the sources themselves, whose addresses are in the last chapter.
A convention, and it is called one
The division into five periods that this book sets out is a convention, and it is the one taught in France. This volume therefore declares its scope from its cover onwards: it describes a French filing system, applied above all to the history of western Europe, and it never passes itself off as a universal description of the past. Other countries divide differently, with just as good reasons, and this book does not compare them.
This is not an opinion of ODERSA. The official history syllabus of the French state school system, published in 2026, writes it itself among the things to be known: the division of historical time is the product of convention and is subject to debate. A public authority that teaches a division and says in the same document that this division is open to argument: that is exactly the honesty this book takes up. One point of method before going further, since this edition is in English: every sentence quoted in this book from a French document is translated by ODERSA, and the original wording is at the address given in the sources chapter.
The practical consequence is simple. Every time this volume gives a boundary date, it also gives the reason for that boundary and, when another one exists, it names it. Dividing dates do not fall from the sky: somebody chose them, for a reason, and that reason is said.
How to use this book
To place a date
Go to the chapter with the great timeline, at the end of the volume. Its table puts in a single order the landmarks the book uses, with the period each one belongs to. That is the page to photocopy or to copy onto a board.
To understand a period
Each period has its chapter, and each chapter follows the same shape: what the word designates, the two boundary dates and why they were chosen, a table of landmarks, what the period changes in people's lives, and what is still argued over.
To prepare a lesson
The tables are designed to be taken as they are. They run to four columns at most, they carry a full caption, and their headers say what each column contains. The licence of this book allows them to be copied, translated and modified.
To check a statement
The sources chapter gives the address of every document used, with the date on which ODERSA consulted it. A fact in this book that you cannot find again at its source is a mistake: report it, the address is in the volume's notice.
The suggested reading order
Three possible ways in, depending on what you are looking for. None is compulsory: the chapters stand on their own.
- If you are starting from nothing
Read in the order of the contents. The first three chapters install the tools: counting time, reading a timeline, knowing the five periods. Without them, the period chapters read like lists of dates. - If you can already read a timeline
Start at the chapter on the five periods, then take the period chapters in whatever order suits you. They do not assume one another: each one gives again the boundary dates it needs. - If it is the method that interests you
Go straight to the two closing chapters, on sources and on dating. They are the ones that answer the question all the others assume: how do we know what we claim to know.
The dates in this book are written with the abbreviations BCE and CE, for Before the Common Era and Common Era. They replace BC and AD, and the counting reference stays exactly the same: only the name changes, and it assumes nobody's religion. This book uses BCE and CE everywhere, and never mixes the two systems; BP, the unit used by dating laboratories, is a third thing and it keeps its own name. The chapter on counting time explains why this choice changes no date at all.
This volume names no class and no school level in its chapters, and that is not an omission. A class name designates neither the same age nor the same syllabus from one country to another, and it changes with every reform. The correspondences with the main school systems of the French-speaking world live in the appendix at the end of the volume, with their sources, and they are given there as an indication for the adult, never as a verdict on a reader.
Acknowledgements
This volume rests on public documents, free of charge and open to anyone. ODERSA names them here because they are the work of institutions that make their knowledge accessible, and because a book that hides what it leans on asks for a trust it has not earned.
The ministère de l'Éducation nationale (the French ministry of education) publishes its teaching syllabuses and their annexes in open access: that is where the periodisation boundaries used here come from, and the sentence recalling that this division is a convention. The Institut national de recherches archéologiques préventives (INRAP, the French national institute for preventive archaeology) puts online an extensive documentation on excavation work and on the history of its own discipline. The ministère de la Culture (the French ministry of culture) publishes complete scientific dossiers on the major archaeological sites, among them Lascaux, where the dating is presented with its successive revisions rather than with one final figure.
The Institut de mécanique céleste et de calcul des éphémérides (the institute of celestial mechanics and ephemeris computation), at the Observatoire de Paris, publishes an explanation of calendars and their reforms that has no equivalent in open access. The Laboratoire de mesure du carbone 14 (the French carbon 14 measurement laboratory), run jointly by several French public bodies, describes its own method and its limits. The Bibliothèque nationale de France (BnF, the French national library) makes available dossiers on ancient scripts and on manuscripts.
No person is named in this volume, and that is a rule of the house, not an oversight. ODERSA is the collective author of what it publishes. The authors of the work this book leans on are credited in the place that counts: the sources chapter, where every document carries its exact address and the date on which it was consulted.