1. Introduction

Today you may have heard a lot about Celts. Today, "Celtic" is often used to describe the languages and respective cultures of Ireland, Scotland, Wales, Cornwall, the Isle of Man and the French region of Brittany. Nationalists in Scotland, Ireland and Wales used the idea of Celtic origin, looking for a way to differentiate themselves from England and assert their right to independence. The Celtic culture has become popular with the European people several times since the 17^th century.

We should be careful: first of all, Celts are not a nation or a people. The term Celts refers to any of a number of peoples in Europe using the Celtic languages, which form a branch of Indo-European languages. So first of all, it’s a unity of similar languages. In the Celtic language family the following ones are still spoken: Irish, Scottish Gaelic and Manx (Goidelic languages) and Welsh, Breton and Cornish (Brythonic languages). While the peoples included into the category of Celtic had different names: Bituriges, Brigantes, Ibernii, etc. Such names as Gauls, Goidhels and Britons are broader terms for groups of peoples. Among them there are many ones whose language is unknown but who have associated cultural traits such as Celtic art found in archaeological evidence. As a result there has been a great debate in scientific circles, termed by John Collis (2003) the "continuous circular argument". Historical theories were developed that all the above given factors were indicative of a common origin, but later theories stated that the culture spread to differing indigenous peoples and they have recently been supported by some genetic studies. Only in the last two decades of the twentieth century did multidisciplinary studies come to bear upon the history of the Celts. Disciplines such as ancient history, palaeolinguistics, archaeology, history of art, anthropology, population genetics, history of religion, ethnology, mythology and folklore studies should all be taken into consideration.

So the word 'Celtic' is often used as an umbrella term for the pre-Roman peoples of Britain, at the same time being challenged by many writers.

The first literary reference to the Celtic people, as keltoi is by the Greek historian Hecataeus in 517 BC. He locates the Keltoi tribe in Rhenania (West/Southwest Germany). In Latin Celta came in turn from Herodotus' word for the Gauls, Keltoi. The Romans used Celtae to refer to continental Gauls, but apparently not to Insular Celts, which were divided into Goidhels and Britons, and possibly other peoples. The English word is modern, attested from 1707 in the writings of Edward Lhuyd.

2. Origins and geographical distribution

The Celtic language family is a branch of the larger Indo-European family, which leads some scholars to a hypothesis that the original speakers of the Celtic proto-language may have arisen in the Pontic-Caspian steppes. However, as the Celts enter history from around 600 BC, they are already split into several languages groups, and spread over much of Central Europe, the Iberian peninsula, Ireland and Britain.

The Celts as a distinct cultural branch of the Indo-European family emerge with the spread of iron-working that led to the development of the Hallstatt culture (c. 700 to 500 BC). Proto-Celtic, the latest common ancestor of all known Celtic languages, is thought to have been spoken in the early first millennium BC.

The Hallstatt culture was succeeded by the La Tène culture, and during the final stages of the Iron Age gradually transformed into the explicitly Celtic culture of early historical times. The La Tène style was highly derivative from the Greek, Etruscan and Scythian decorative styles with whom the La Tène settlers frequently traded.

The indigenous populations of Britain and Ireland today may be primarily descended from the ancient peoples that have long inhabited these lands, before the coming of Celtic and later Germanic peoples, language and culture. As to the original culture and language, little is known, as we could easily see. Some remnants may be found in the naming of some geographical features, such as the rivers Clyde, Tamar, Thames and Tyne, whose etymology is unclear but may certainly derive from a pre-Celtic substrate.

By the Roman period, however, most of the inhabitants of the isles of Ireland and Great Britain (the ancient Britons) were speaking Goidelic or Brythonic languages, close counterparts to Gallic languages spoken on the European mainland.

Historians explained this as the result of successive invasions from the European continent by diverse Celtic-speaking peoples over the course of several centuries. Later research indicated that culture had developed gradually and continuously. So other scholars stated that the native late Bronze Age inhabitants gradually absorbed European Celtic influences and language. The very few continental La Tène culture style objects which had been found in Ireland could have been imports, or the possessions of a few rich immigrants, further supporting this theory of cultural exchange rather than migration. In the 1970s this model was taken to an extreme, popularised by Colin Burgess in his book The Age of Stonehenge which theorised that Celtic culture in Great Britain "emerged" rather than resulted from invasion and that the Celts were not invading aliens, but the descendants of the people of Stonehenge. The existence of Celtic language elsewhere in Europe, however, and the dating of the Proto-Celtic culture and language to the Bronze age, makes these claims of continuity impossible.

A number of genetic studies have also supported this model of culture and language being absorbed by native populations. The study in University College, London showed that genes associated with Gaelic names in Ireland and Scotland are also common in certain parts of Wales and are similar to the genes of the Basque people, who speak a non-Indo-European language. This similarity suggests that 'Celtic' culture and the Celtic language may have been imported to Britain by cultural contact, not mass invasions, that is by networks of trade and kinship — not by war and conquest around 600 BC. There was certainly a large folk migration from central Europe westwards during the early Iron Age but it’s a question whether or not people from this movement actually reached Great Britain in significant enough numbers to constitute an invasion.