The historical Celts were a diverse group of tribal societies in Iron Age Europe. Proto-Celtic culture formed in the Early Iron Age in Central Europe (Hallstatt period, named for the site in present-day Austria). By the later Iron Age (La Tène period), Celts had expanded over a wide range of lands: as far west as Ireland and the Iberian Peninsula, as far east as Galatia (central Anatolia), and as far north as Scotland.
The earliest direct attestation of a Celtic language are the Lepontic inscriptions, beginning from the 6th century BC. Continental Celtic languages are attested only in inscriptions and place-names. Insular Celtic is attested from about the fourth century AD in ogham inscriptions. Literary tradition begins with Old Irish from about the eighth century. Coherent texts of Early Irish literature, such as the Táin Bó Cúailnge, survive in 12th century recensions.
By the early first millennium AD, following the expansion of the Roman Empire and the Great Migrations (Migration Period) of Germanic peoples, Celtic culture had become restricted to the British Isles (Insular Celtic), and the Continental Celtic languages ceased to be widely used by the sixth century. "Celtic Europe" today refers to the lands surrounding the Irish Sea, as well as Cornwall and Brittany on either side of the English Channel.
Names and terminology
The origin of the various names used since classical times for the people known today as the Celts is obscure and has been controversial. In particular, there are actually 19 records of the term 'pictish' being used in connection with the inhabitants of Ireland and Britain prior to the 18th century.
The Latin name Celtus (pl. Celti or Celtae; Greek Κέλτης pl. Κέλται or Κελτός pl. Κελτοί, Keltai or Keltoi) seems to be based on a native Celtic ethnic name. However, the first literary reference to the Celtic people, as Κελτοί (Κeltoi), is by the Greek historian Hecataeus of Miletus in 517 BC; he says that the town of Massilia (Marseille) is near the Celts and also mentions a Celtic town of Nyrex (possibly Noreia in Austria). Herodotus seems to locate the Keltoi at the source of the Danube and/or in Iberia, but the passage is unclear.
The English word Celt is modern, attested from 1707 in the writings of Edward Lhuyd whose work, along with that of other late 17th century scholars, brought academic attention to the languages and history of these early inhabitants of Great Britain.
Latin Gallus might originally be from a Celtic ethnic or tribal name, perhaps borrowed into Latin during the early 400s BC Celtic expansions into Italy. Its root may be the Common Celtic *galno, meaning 'power' or 'strength'. The Greek Galatai seems to be based on the same root, borrowed directly from the same hypothetical Celtic source which gave us Galli (the suffix -atai is simply an ethnic name indicator).
The English form Gaul comes from the French Gaule and Gaulois, which is the traditional rendering of Latin Gallia and Gallus, -icus respectively. However, the diphthong au points to a different origin, namely a Romance adaptation of the Germanic *Walha-. The English word 'Welsh' originates from the word wælisc, the Anglo-Saxon form of walhiska-, the Germanic word for "foreign".
'Celticity' generally refers to the cultural commonalities of these peoples, based on similarities in language, material artifacts, social organisation and mythological factors. Earlier theories were that this indicated a common racial origin but more recent theories are reflective of culture and language rather than race. Celtic cultures seem to have had numerous diverse characteristics but the commonality between these diverse peoples was the use of a Celtic language.
'Celtic' is a descriptor of a family of languages and, more generally, means 'of the Celts,' or 'in the style of the Celts'. It has also been used to refer to several archaeological cultures defined by unique sets of artifacts. The link between language and artifact is aided by the presence of inscriptions.
Today, the term 'Celtic' is generally used to describe the languages and respective cultures of Ireland, Scotland, Wales, Cornwall, the Isle of Man and Brittany, also known as the Six Celtic Nations. These are the regions where four Celtic languages are still spoken to some extent as mother tongues: Irish Gaelic, Scottish Gaelic, Welsh, and Breton plus two recent revivals, Cornish (one of the Brythonic languages) and Manx (one of the Goidelic languages). There are also attempts to revive the Cumbric language (a Brythonic language from Northwest England and Southwest Scotland). 'Celtic' is also sometimes used to describe regions of Continental Europe that have Celtic heritage, but where no Celtic language has survived; these areas include the western Iberian Peninsula, i.e. Portugal, and north-central Spain (Galicia, Asturias, Cantabria, Castile and León, Extremadura), and to a lesser degree, France.
'Continental Celts' refers to the Celtic-speaking people of mainland Europe.
The Celtic languages form a branch of the larger Indo-European family. By the time speakers of Celtic languages enter history around 400 BC (Brennus's attack on Rome in 387 BC), they were already split into several language groups, and spread over much of Central Europe, the Iberian peninsula, Ireland and Britain.
Some scholars think that the Urnfield culture of northern Germany and the Netherlands represents an origin for the Celts as a distinct cultural branch of the Indo-European family. This culture was preeminent in central Europe during the late Bronze Age, from ca. 1200 BC until 700 BC, itself following the Unetice and Tumulus cultures. The Urnfield period saw a dramatic increase in population in the region, probably due to innovations in technology and agricultural practices. The Greek historian Ephoros of Cyme in Asia Minor, writing in the fourth century BC, believed that the Celts came from the islands off the mouth of the Rhine who were "driven from their homes by the frequency of wars and the violent rising of the sea".
The spread of iron-working led to the development of the Hallstatt culture directly from the Urnfield (c. 700 to 500 BC). Proto-Celtic, the latest common ancestor of all known Celtic languages, is considered by this school of thought to have been spoken at the time of the late Urnfield or early Hallstatt cultures, in the early first millennium BC. The spread of the Celtic languages to Iberia, Ireland and Britain would have occurred during the first half of the 1st millennium BC, the earliest chariot burials in Britain dating to ca. 500 BC. Over the centuries they developed into the separate Celtiberian, Goidelic and Brythonic languages.
The Hallstatt culture was succeeded by the La Tène culture of central Europe, and during the final stages of the Iron Age gradually transformed into the explicitly Celtic culture of early historical times. Celtic river-names are found in great numbers around the upper reaches of the Danube and Rhine, which led many Celtic scholars to place the ethnogenesis of the Celts in this area.
Diodorus Siculus and Strabo both suggest that the Celtic heartland was in southern France. The former says that the Gauls were to the north of the Celts but that the Romans referred to both as Gauls. Before the discoveries at Hallstatt and La Tene, it was generally considered that the Celtic heartland was southern France, see Encyclopedia Britannica for 1813.
Almagro-Gorbea proposed the origins of the Celts could be traced back to the third millennium BC, seeking the initial roots in the Bell Beaker culture, thus offering the wide dispersion of the Celts throughout western Europe, as well as the variability of the different Celtic peoples, and the existence of ancestral traditions an ancient perspective.
Meanwhile, genetics, history, and archaeological researcher and writer Stephen Oppenheimer suggests the Celts were a Mediterranean people first established in what is now southern France by the end of the last glacial maxum, around 11,000BC. From there through further integration with what might have been proto-Basque populations, these people spread outward into Italy, Spain, the British Isles and Germany. Indeed, Celtic origin myths recorded in Medieval Scotland and Ireland suggest a possible beginning in Anatolia and then to Iberia via Egypt. But, in his 2006 book The Origins of the British, revised in 2007, he argued that neither Anglo-Saxons nor Celts had much impact on the genetics of the inhabitants of the British Isles, and that British ancestry mainly traces back to the Palaeolithic Iberian people, now represented by Basques, instead.
The Proto-Celtic language is usually dated to the early European Iron Age. The earliest records of a Celtic language are the Lepontic inscriptions of Cisalpine Gaul, the oldest of which still predate the La Tène period. Other early inscriptions are Gaulish, appearing from the early La Tène period in inscriptions in the area of Massilia, in the Greek alphabet. Celtiberian inscriptions appear comparatively late, after about 200 BC. Evidence of Insular Celtic is available only from about AD 400, in the form of Primitive Irish Ogham inscriptions. Besides epigraphical evidence, an important source of information on early Celtic is toponymy.
In various academic disciplines the Celts were considered a Central European Iron Age phenomenon, through the cultures of Hallstatt and La Tène. However, archaeological finds from the Hallstatt and La Tène cultures were rare in the Iberian Peninsula, and did not provide enough evidence for a cultural scenario comparable to that of Central Europe. It is considered equally difficult to maintain that the origin of the Peninsular Celts can be linked to the preceding Urnfield culture, leading to a more recent approach that introduces a 'proto-Celtic' substratum and a process of Celticization having its initial roots in the Bronze Age Bell Beaker culture.
The Iron Age Hallstatt (c. 800-475 BC) and La Tène (c. 500-50 BC) cultures are typically associated with Proto-Celtic and Celtic culture.
The La Tène culture developed and flourished during the late Iron Age (from 450 BCE to the Roman conquest in the 1st century BCE) in eastern France, Switzerland, Austria, southwest Germany, the Czech Republic, Slovakia and Hungary. It developed out of the Hallstatt culture without any definite cultural break, under the impetus of considerable Mediterranean influence from Greek, and later Etruscan civilizations. A shift of settlement centres took place in the 4th century.
The western La Tène culture corresponds to historical Celtic Gaul. Whether this means that the whole of La Tène culture can be attributed to a unified Celtic people is difficult to assess; archaeologists have repeatedly concluded that language, material culture, and political affiliation do not necessarily run parallel. Frey notes that in the 5th century, "burial customs in the Celtic world were not uniform; rather, localised groups had their own beliefs, which, in consequence, also gave rise to distinct artistic expressions". Thus, while the La Tène culture is certainly associated with the Gauls, the presence of La Tène artefacts may be due to cultural contact and does not imply the permanent presence of Celtic speakers.
Polybius published a history of Rome about 150 BC in which he describes the Gauls of Italy and their conflict with Rome. Pausanias in the second century BC says that the Gauls "originally called Celts live on the remotest region of Europe on the coast of an enormous tidal sea". Posidonius described the southern Gauls about 100 BC. Though his original work is lost it was used by later writers such as Strabo. The latter, writing in the early first century AD, deals with Britain and Gaul as well as Hispania, Italy and Galatia. Caesar wrote extensively about his Gallic Wars in 58-51 BC. Diodorus Siculus wrote about the Celts of Gaul and Britain in his first century History.