During the last glaciation, vast areas of northern Europe, including the British Isles, were uninhabited. This glaciation reached its peak at about 20,000 BC (Late Glacial Maximum, LGM), and it wasn't until the beginning of the Holocene (about 12,000 BP) with milder climatic conditions, that these territories started to be repopulated from southern refugia. Population genetics studies show that the Franco-Iberian LGM Refugium played a major role in this repopulation, with a series of relevant gene clusters that can be traced back to that original area. Some authors, e.g. Oppenheimer, have also suggested that this Mesolithic expansion from the various rrfugia is the most important component in today's European populations; other authors suggest that the role of later oppulation movements, e.g. during the Neolithic, has left a more significant mark. This is of course a matter of current debate, and one that has important implications for the study of European prehistoric languages. Now, what was this Franco-Iberian refuge exactly?
Sometimes, it is referred to simply as the Iberian refuge, but I prefer the other name (Franco-Iberian, or Franco-Cantabrian) because I think it's a more accurate term. In his book (Origins of the British), Stephen Oppenheimer defines it as follows: (p. 118): "The refuge for south-west Europe was spread either side of the Pyrenees in southern and eastern France, the Basque Country, and other northern coastal parts of Spain such as Galicia and Catalonia." I'm not so sure of that. If we take a look at a physical map of the Iberian Peninsula, we realize that it is in general composed of high lands and mountainous terrain. In fact, Spain is the second highest country in Europe, after Switzerland, and the area of Castilla-León, sorrounded by mountains, is the highest plateau in Europe (with cities like Burgos, at an altitude of 929 m.). In present-day climatic conditions, these natural features would impose some limitations to population or linguistic exchange. In the hard conditions of the LGM, and also in later cold spells, e.g. the Younger Dryass, they probably meant complete isolation. The Mediterranean areas of Iberia, including Catalonia, were probably cut off from the Cantabrian coast, so they probably did not participate in the repopulation of north-west Europe. As I see it, there is an axis dividing the Iberian Peninsula into two distinct prehistoric areas: on the one hand, the Atlantic Façade, comprising Portugal and some regions of northern and central Spain; on the other, a Mediterranean Façade, connected with southern France and Italy. This division, caused by climatic and geographic features, is also reflected in the distribution of languages in prehistory: Celtic in the west and Iberian on the Mediterranean, as can be seen in the map of the left (source: Arkeotavira). How old are these linguistic borders? What were the languages spoken by those people who repopulated the British Isles and other northern regions from the Franco-Iberian refuge? These are difficult questions to answer. Geographic features are an important factor in population movements, as they define the possible routes of communication and the chances for interaction. This can clearly be seen during the LGM, the most hostile environment that can be imagined for human populations in Europe, but also in other periods, with milder climatic conditions.
In some previous posts (e.g. here) I have suggested some possible scenarios for the languages of the Iberian Peninsula in pre-Roman times. One of the hypotheses, as stated by Xaverio Ballester and other authors, is that the speakers of Iberian languages arrived at a later period, settling over a territory where IE (possibly Italid) languages were spoken. But where did these Iberian-speakers come from? A possible candidate is Aquitaine, in south-west France, as some parallels can de drawn between the ancient languages of the Aquitani and Iberian. It has also been argued that Iberian is connected with Basque, and this idea was actually quite popular in the 20th century, leading to some simplistic equations of Basque and Iberian which were more enthusiastic than scientifically sound. In any case, it is reasonable to see some possible links between the languages of the Basques, the Aquitani and the Iberians. Now, what is the possible geographic connection between these territories? If we look at the first map again, we find that there is actually a natural corridor uniting those areas: the Garonne River Valley, situated between the Pyrenees and the French Massif Central; at its centre, the city of Toulouse, a strategic point in this route. Was this natural corridor shut off during LGM? It would be interesting to know.
Whenever one attempts to make sense of the languages of western Europe, one is forced to face a familiar mystery: the presence of an unexpected non-IE linguistic isolate: Basque. And to make matters worse, the Basque-speaking area is actually at the heart of the Franco-Iberian LGM refugium. According to the German linguist Theo Vennemann, the people in the Franco-Iberian refugium spoke languages related to Basque, and they spread them through vast areas of western and northern Europe. These languages were later superseded by Indo-European (except of course in the Basque Country) and their traces, as Vasconic Substratum, can be found in the vocabulary of some European languages, including toponymical terms. Vennemann's theory has not been accepted in general, and I personally think it's not tenable (I'll discuss it in a future post). However, it presents a coherent explanation in terms of prehistoric events. Now, is there an alternative explanation? Let's try.
The question is: why would a language, in this case Basque, be excluded from the opportunity of expanding to a new territory, in this case post-Ice-Age northern Europe, when the opportunity arose? First, it must be said that, in theory, there's no reason to believe that Basque was spoken in that area at such an early age (the Mesolithic), but in any case, for the purposes of this investigation, let's assume that this was the case. The Basque country of today occupies the coastal corner of land that connects Spain and France. At first sight, this would have been the natural route for any population transfer from the LGM refugium to the north. However, let's remember that at that precise moment the coastal line was different from the one we have today; the sea level was much lower, and the lowlands extended well into the Antlantic. At least in theory, it is possible that some populations along the Cantabrian coast, speakers of a non-Basque language, moved to the north, bypassing the highland areas where Basque-related languages were spoken and actually impeding any possible expansion of this language group into the new horizon created by the receding ice. And it can also be argued that these 'opportunists' from the Cantabrian refuge were speakers of some form of Indo-European, but that's of course a different discussion. In any case, is it reasonable to suppose that the Basque-speaking population just missed the chance for expansion? The situation is not impossible in itself. To illustrate the point, I will provide an example which bears some distant resemblance: the conquest and colonization of America.
The discovery of America opened a new horizon for European populations and languages, but who took the chance? Obviously, there is a geographic factor in this: it was the areas around the Atlantic that were involved in the whole process. First the Spanish and the Portuguese, then the English, the French and the Dutch. Let's take a look at the Spanish expansion: who took part in it? Basically, it involved people from the west side of the axis (see above), mainly from areas such as Extremadura or Andalusia. There was little or no involvement of people from the Mediteranean coast in the whole event. Consequently their language (Catalan) played no role in the story. This can be explained in geographic terms but also, more importantly, in socio-economic terms: the eastern regions of Spain are in a different context, one that connects them to other Mediterranean territories. In addition, the discovery of America coincided with a time of decadence for the Catalan language, with Spanish as the language of the new emerging power.