To study the history of the Celtic people, we first must have a firm grounding in historical evidence. Modern historians have a number of tools at their disposal, and this article offers an overview of some of the major types of evidence.

To understand historical evidence and the Celtic world in all its complexity, we have to think about two interlocking stories. The first story is the story of what actually happened in the areas we now think of as Celtic in some fashion, as we currently understand it. The second story, which is equally fascinating, is the story of how the legend of the Celts developed over time and influenced the politics and society of the Celtic realms in particular, but also of the whole world.
What We Talk about When We Talk about Evidence
To tell these two stories, we will need to discuss several kinds of evidence. Scholars like to talk in terms of evidence, which is simply the material they use to create a picture of what happened in the past. The Celtic story draws on many different academic disciplines, or approaches to knowledge, and, in many ways, the story of the Celts also allows us to tell a fascinating story of how these disciplines developed. Here, I just want to say a few words as we get started about these different disciplines and where they enter the story of the Celts.
This is a transcript from the video series The Celtic World. Watch it now, on Wondrium.
So let me say something about these various approaches to knowledge that are going to help us understand the Celtic phenomenon, and I’m going to discuss them roughly in the order in which they developed as distinct methods for approaching the study of the past. Each approach has its own strengths, but also important limitations that we need to be aware of so that we can interpret the evidence in the best possible way.
Learn more about evidence and the nature of science
I’m going to start with history, which is my own discipline. The most important method used by historians is the analysis of written texts. We actually have lots of texts written about the ancient Celts, and we can learn a lot about the Celts from the works written by the ancient Romans and Greeks who encountered them.
Starting from about the 6th century, the residents of the Celtic Fringe themselves wrote an enormous amount of material that we can read and analyze, though some of it is very obscure and difficult to understand. But we have lots and lots of written evidence that we can use to learn about the Celts, using traditional methods of textual analysis. Of course, these methods of analysis are very old; historians have been analyzing written texts for more than two thousand years. But we will see that the ways in which we analyze texts can change over time. History is a discipline that is always renewing itself.
Of course, textual analysis has many drawbacks as well as advantages. We are limited by what remains. There are many things we’d like to know about the past, but if nobody chose to write them down, or if texts that recorded this information were lost, we are out of luck. We are also at the mercy of the biases of those who wrote the texts that do survive. These authors were not necessarily trying to enlighten us on the points about which we have questions. In some cases, we can tell that authors are distorting the past for their own purposes. In other cases, we probably don’t even register the distortion; we are being fooled. But we must proceed bravely anyway.
A Quick Introduction to Historical Linguistics
Another discipline that is absolutely essential to understanding the Celts is historical linguistics, the study of how languages are related to each other and how they change over time. Languages can be related to each other almost the way members of a family are related to each other, or like branches of a tree. Historical linguists try to determine how closely related to each other different languages are, and this can allow them to make certain hypotheses about the people who spoke them. People who speak closely related languages may have started out living close together, and sometimes the specific words in those languages can tell us something about where the people might have lived in the past; for example, if a language has a lot of words for snow, the people who spoke it probably came originally from an area with cold winters.
Learn more about historical linguistics and the study of culture
Historical linguistics is crucial to our story for many reasons. One of the most important of these is because it is through linguistics that the connection among all the Celtic peoples was first made, and particularly the connection between the residents of Ireland and Britain and the Celts of the continent, starting in the 16th century. It turned out that the languages spoken in Ireland and Britain were related to the language spoken in Gaul in the time of Julius Caesar. We will have much more to say about this connection later. So, it was really historical linguistics that helped create the idea of the Celts as a unified phenomenon in the first place. Since the 1990s, historical linguists have been doing pioneering work in trying to determine whether newly found stone inscriptions from Spain and northern Italy were written in Celtic languages or not. The work of linguists, then, is crucial to the question of determining who is and is not a Celt, a question to which we will return many times in this course.
Linguistics can also tell us some very important things about historical developments. For example, if we understand how the Celtic languages changed over time, we can often tell when a particular important event took place because of how that event is recorded in the Celtic languages. An important example is the Christianization of Ireland. We know that Ireland started to be Christianized in the 4th century, because we know that certain words about Christianity that were borrowed from Latin into Old Irish would look one way if they were borrowed in the 4th century, and another way if they were borrowed in the 6th century, due to the way the language had changed in the meantime. The study of the Celtic languages will play a very important role in this story.
Finally, of course, historical linguistics is vital because we need a thorough understanding of the Celtic languages themselves if we are to understand the texts that were written by the people we are trying to study. Here is where the techniques of textual analysis and linguistic analysis intersect. Historians and linguists have to work hand in hand, particularly when studying the Celts. As I said, the field of historical linguistics has been part of the effort to understand the Celts since the 16th century, and as the discipline of linguistics as a whole has advanced, new insights about the Celtic languages are continually coming to light. Like history, linguistics is a relatively old discipline that is still producing new information.
Of course, linguistics, like textual analysis, has its own drawbacks. Languages are very complex, and if you are trying to see relationships between languages, it can be easy to focus on the features that look similar and ignore the differences, or vice versa, so caution is required.
Archaeology and the Study of Artifacts
Another important academic discipline that is vital to study of the Celts is archaeology, which really developed as an academic discipline starting in the 19th century. If historians concentrate on texts, and linguists concentrate on the languages in which those texts were written, archaeologists work without any texts at all, although of course they are happy to draw on texts when they prove helpful. The work of an archaeologist is focused almost entirely on physical artifacts.
Academic archaeology grew out of the sort of treasure hunting we might associate with Indiana Jones, but it quickly settled into the disciplined pursuit of knowledge about cultures from the past, as these cultures reveal themselves in the objects they created and the structures they built.
Learn more about recovering lost worlds through archaeology
Archaeologists created the idea of the discrete “culture” that could be identified by groups of artifacts occurring together; if you find certain kinds of pots, certain kinds of weapons, and certain kinds of personal objects, like jewelry, together in a region, you are probably looking at people who considered themselves to belong to the same ethnic group. The discrete culture theory that archaeologists developed has proved very influential in the creation of the idea of the Celts. Archaeology is very important particularly to the study of the ancient Celts because very, very little written material has survived from the Celts themselves.

But the drawback of archaeology is precisely the fact that the artifacts cannot talk. We can’t be sure from looking at pots or brooches what languages their owners spoke, or to which ethnic groups artifact owners believed themselves to belong. And we are also limited by what has happened to survive, and what archaeologists have happened to find.
Living in the Future: DNA Evidence
But we are also going to talk about a brand-new kind of evidence: DNA evidence. Scientists can now do two kinds of DNA analysis that can help us understand the ancient Celts. They can analyze the DNA of bones preserved in ancient burials, and they can also analyze the DNA of living persons to help them understand something about where different populations came from and how they are related to each other. Is there something distinctive genetically about the Celtic regions? How does DNA shed light on some of the big questions about Celtic identity?
Historical evidence covers a lot of ground, from ancient texts to the latest scientific advances, and all of it will help us to understand the world of the Celts.