Language continuity in Europe (III): Ireland

Who brought Celtic languages to Ireland? And when? - It seems that there is no easy answer to these questions.

In general, islands are a good place to study population and language evolution, because they offer a more limited range of variation and better chances for establishing the chronology of events than in continental land. The British Isles are not an exception. In fact, there’s a detail that makes this area even more interesting for the researcher: due to their location in the northern Atlantic, the British Isles have been greatly affected by major climatic changes, especially glaciations. It is supposed, for example, that by the time of the Late Glacial Maximum (LGM), i.e. the coldest period of the last ice age (about 22,000 to 17,000 years BP), the British Island became a frozen desert, with no possibilities for human life. The re-population of the British Isles started from zero when the ice started to recede.

In the comments to a recent post in this blog we had an interesting discussion about the Celts. One of the commentators, Ian, suggested a book about this topic: Stephen Oppenheimer’s The Origins of the British (see below for full bibliographic details). I had never heard about this book before, and I found it interesting so I ordered it on the Internet and a week later I had it in my hands. Reading it was just a matter of days. No doubt about it, this is the ‘21st-century’ at work! Speed and availability. Ideal for inquiring minds.

In his book, Stephen Oppenheimer offers a detailed analysis of the history of human populations in the British Isles. Being a geneticist, he focuses primarily on the genetic material of these populations, combining it with other sorts of evidence, e.g. from archaeology or history texts. His research is quite comprehensive: he analyses and discusses the results obtained by previous authors, e.g. Sykes and Richards, and offers new, generally more accurate explanations for the history of British gene clusters. I had never seen such a complete and detailed account of western European genetic history, and, not having yet read any review of this book by other geneticists, I am not in a position to say if all the details of Oppenheimer’s theory are acceptable or not. In any case, I have the impression that the overall picture offered in this book is coherent and logical, and is bound to become a reference point in any future study of western European prehistory. Now, what is this ‘overall picture’? It is difficult to summarize Oppenheimer’s book in just one post, and I suppose I’ll be talking about it in future occasions. There is an article by Oppenheimer (published in Prospect), where you can find some of the main points in his theory.

The re-colonization of the British Isles took several steps, starting about 16,000 years ago after the LGM. The first colonizers came from the Franco-Spanish refuge, an area in northern Iberia and southwestern France where human life had not been interrupted by the ice. This Iberian gene flow is by far the most important element in the genetic components of the populations in the British Isles, especially in Ireland, Wales, Cornwall and other western areas. At about 12,300 BP there was another glacial period, called Younger Dryas, which also had an impact on this area. It is thought, however, that human population did not disappear from the British Isles in the Younger Dryas, even though there was a significant demographic drop. The Younger Dryas was much shorter than the LGM: by 11,000 BP the climate started to become much milder, like the one we have today. This period, known as Mesolithic, saw a new process of colonization from the continent, which two main lines: from Iberia and from northwestern Europe. This double migration path is actually a recurrent pattern in the prehistory of the British Isles, which is repeated in later times (Neolithic, Bronze Age, Iron Age). According to Oppenheimer, this pattern of migration set the basis for the separation between Celtic and Germanic areas in the British Isles. In other words, the boundaries between these two areas are not the consequence of recent historical events, like the Anglo-Saxon invasion, but were established in a process that started in the Late Upper Paleolithic, after the LGM. Basically speaking, what we have here is a pattern of continuity of human populations. The genetic input from the earlier times (Paleolithic or Mesolithic) is the most relevant component in the genetic material found in populations of that area today. The contribution of later migrations, e.g. in the Neolithic, is considerably lower, which means that the expansion of agriculture and metallurgy was not the consequence of massive migration, but a local development. This is especially true in the case of Ireland, as we will see.

It is not clear if Ireland was re-colonized by humans immediately after the LGM, but there are some indications pointing in this direction. There is clear evidence, however, of human migration into Ireland during the Mesolithic, mainly from Iberia. On the left you can see a map from Oppenheimer’s web-page, with the distribution of one of the gene clusters from Iberia, following a typical pattern. The impact of later migrations into Ireland is generally considered low, in comparison with eastern Britain, which was under the influence of migrations from northwestern Europe. According to Oppenheimer, intrusive lines in the Neolithic account for 6-9 % of all Irish genes. This doesn’t mean that Ireland was isolated from the rest of the world in prehistory; in fact there were strong links between Ireland and other Atlantic European areas, as shown by Cunliffe and other authors who talk about the ‘Atlantic Façade’. But it is clear that the Neolithic and other later prehistoric periods did not involve a relevant population input in Ireland. Now, let’s go back to the initial question of this blog: Who brought Celtic languages to Ireland? And when? – There are several possibilities: in the Mesolithic, as the Continuity Theory proposes; in the Neolithic (Colin Renfrew’s theory); or in the Iron Age, as some people still think. - At this point, Oppenheimer asks a couple of interesting questions (p. 246): “how could a new language arrive during the Neolithic without people? (...) Was 6% invasion enough to change culture and language?” For him, the possibility of a Paleolithic or Mesolithic origin of Celtic languages in Ireland is “unlikely” (p. 222), but not impossible. It is clear that the door is open for new research on the languages and populations of the British Isles, and of Ireland in particular, with new perspectives and new tools that were not available just a few decades ago. And it is also becoming quite obvious that the Central-European theory of Celtic origins, which puts them in connection with the Halstatt or the La Tène Iron-Age cultures of the first millennium BC, is quite unacceptable.

References:
- Oppenheimer, Stephen (2007). Origins of the British. London: Constable and Robinson [first edition, hardcover: 2006, London: Constable and Robinson].