Most of what we know of the Celts comes from the Romans, their victims and vanquishers, and from the weapons and ornaments that they buried with their dead. From these traces we can visualize a sophisticated people who dominated Europe for five hundred years.

Two new groups of people emerge in Central Europe during the late Neolithic (New Stone Age) period, one certainly immigrant. Each group may be distinguished archaeologically by characteristic artifacts found in their respective burial sites. One was a Bell Beaker or drinking vessel. We now refer to this group as the Beaker folk. There is still some doubt as to the origins of the Beaker folk, some say Iberia, and some say Central Europe itself. Never-the-less it is believed that they emerge as an independent cultural group around 3000 B.C.E..

The second group is characterized by a perforated battle-axe of stone. Similarly, we now refer to this group as the Battle-Axe folk. Evidence points towards origins in the steppe-lands of southern Russia, between the Caucasus and the Carpathian mountains. The Battle-Axe folk may be attributed with the initial spread of the Indo-European group of languages. The Indo-European group of languages encompasses most of those current in present-day Europe. In Central Europe the Beaker folk and Battle-Axe folk fused to become one European people. Shortly thereafter began the Bronze Age in Europe. It is unclear whether the arrival of the two groups influenced the arrival of the Bronze Age or not. Many think that contact with the Mediterranean and beyond may have influenced this.

From this period onwards the line of continuity which leads directly to the historic Celts may be traced from the archaeological evidence. This is identified by the successive Únêtice, Tumulus and Urnfield cultures of the Central European Bronze Age. The Únêtice culture appears to have emerged from the fusion of Battle-Axe and Beaker peoples and their immediate descendants. The Únêtice culture became the pre-eminent culture in Central Europe by the middle of the second millennium B.C.E.. Because of rich mineral deposits and control of trade routes between the south-east (early Mediterranean cultures) and the more distant parts of Europe, the Únêtice people prospered.

The Tumulus culture which followed the Únêtice, and from which they descended, dominated Central Europe during much of the second part of the second millenium B.C.E.. As the name implies, the Tumulus culture is distinguished by the practice of burying the dead beneath burial mounds. During this period trade contacts with the south-east remained intact and were probably expanded. The Tumulus culture flourished without any disruption of local peoples by large-scale immigration. This was to end, however, toward the close of the second millennium B.C.E., when there is evidence of wide-spread disruption which affected the "higher civilizations" to the south-east and curbed trade.

With the emergence of the Urnfield culture of Central Europe, there appear a people whom some scholars regard as being 'proto-Celtic', in that they may have spoken an early form of Celtic. As the name suggests, the people of the Urnfield culture cremated their dead and placed the remains in urns which were buried in flat cemeteries without any covering mound. The period of the Urnfield culture, like that of the Tumulus culture, was one of expansion, particularly during the first millennium B.C.E. It is during the period of the Urnfield culture that the Bronze Age was at its peek in Central Europe. They produced weapons, tools, eating and cooking vessels, etc. all out of Bronze. From the Urnfield Culture, the Celts emerge as an agricultural people.

Whereas the Urnfield people may justifiably be considered to have been proto-Celtic, their descendants in Central Europe, the people of the Hallstatt culture, were certainly fully Celtic. The Hallstatt culture and its successor, that of La Tène, together represent the iron-using prehistoric peoples of much of Europe. These are the Keltoi, the Galli and Galatae of classical writers. The two cultures are named after sites at which were found archaeological artifacts now considered to be representative of a particular stage of each culture. Hallstatt is a village in Central Austria at which was found an important cemetery; La Tène is near the north-eastern end of Lake Neuchâtel, in western Switzerland. In rough terms the Hallstatt culture existed from approximately 1200 to 500 B.C.E., with some overlap of the Urnfield culture. The La Tène culture in the parts of Europe which would soon become part of the Roman Empire ended with the arrival of the Romans. Beyond the Empire, such as Ireland and Northern Britain (modern day Scotland) the La Tène culture flourished until about 200 C.E..

A French definition says that ‘prehistory stops with the first written document'. By this definition the Celts qualify as a prehistoric people. They were the first of the prehistoric peoples north of the Alps whose names were known to the Greek and Roman world, for they shared common features, including some linguistic similarities. The languages of the Celts belong to the great Indo-European family of languages, which also includes Anatolian, Hellenic, Italic, Illyrian, Slavonic, Baltic, Germanic, Armenian, Indo-Iranian, and Tocharian.

We can hypothesize that, at some point of their historical development, the Celts spoke a common Celtic language. Celtic scholars have supposed this common Celtic may have been spoken just before the start of the first millennium B.C.E. during the Urnfield/Hallstatt eras. Soon after, five(?) distinct dialects emerged.

Unfortunately, since no version of Hispano-Celtic, Gallic, or Lepontic has survived, we do not know whether they were distinct dialects, or whether they also were part of the P-Celtic and Q-Celtic variety. Pictish seems to have included a large element of Gallic or Welsh, but of an early type no longer identical with the Welsh of today.

Goidelic is said to be an older form than Brythonic, which may have developed from Goidelic at a later stage. Brythonic simplified itself in its case endings and in changes of gender. The major difference between the two dialects, is the substitution of P for Q in Brythonic, hence the terms P-Celtic and Q-Celtic. This is based on the Indo-European sound "qu(kw)". The sound in Goidelic later became represented by "c" (always hard), which in Bythonic it was replaced by "p". An example of this can be seen in the word for son. In Goidelic it is "mac", in Bythonic it is "map" or "mab".

The Celts did not use the art of writing to any great extent and then only near the end of their independence. A form of writing called Ogham may have been used by certain members of Celtic society, most likely the druids, to record important information. In general, however, they chose to record their past and traditions orally and communicated with other nations only by word-of-mouth. Like many communities all over the world, the Celts paid great attention to the development of an advanced oral technique as a vehicle for the transmission of their thoughts. Among illiterate peoples, the training of the memory is cultivated to a degree unheard of among readers of books, and the proficiency of the Gauls in this respect is commented on by Caesar:

‘It is said that [the Druids] have to memorize a great number of verse - so many, that some of them spend twenty years at their studies. The Druids believe that their religion forbids them to commit their teachings to writing, although for most other purposes, such as public and private accounts, the Gauls use the Greek alphabet. But I imagine that this rule was originally established for other reasons - because they did not ant their doctrine to become public property, and in order to prevent their pupils from relying on the written word and neglecting to train their memories; for it is usually found that when people have the help of texts, they are less diligent in learning by heart, and let their memories rust.'

The whole intellectual life of the Gauls in pre-Roman times was carried on by means of oral teaching, and closely associated with their trained eloquence was their power of memorizing. The education of the young and the intellectual life of all classes was carried on by two classes of men known as druids and bards, who taught entirely by means of poetry orally transmitted. Despite the absence of books their teaching was a intensive and included such subjects as astronomy, nature, religion, and philosophy.

In trying to understand the motivations, attitudes, philosophies, and laws of the Celts, we are handicapped by the early prohibition of the Celts against committing their knowledge to written record. So it was not until the Greeks and Romans began to write their accounts of the Celts, sometimes culturally misconceived and invariably biased, that the Celts emerged into recorded history. So, we view the ancient Celts of continental Europe through Greek and Roman eyes, since they have left no written record of themselves. However, when the insular Celts of Britain and Ireland began to put their knowledge into written form in the Christian era it was not too late to form a perspective, bearing in mind the cultural changes from early times.

Celtic art is considered the first great contribution to European art made by non-Mediterranean peoples. Its roots go back to the artisans of the Urnfield culture and the Hallstatt Culture (8th century BC to 5th century BC)bc at the beginning of the Iron Age. It flowered in the period of the La Tène culture. Although Celtic art was influenced by ancient Persian, Greek, Etruscan, and Roman art and by that of the nomads of the Eurasian steppes, it developed distinctive characteristics. These are evident in its major artifacts—weapons, vessels, and jewelry in bronze, gold, and occasionally silver. Many of these objects were made for chieftains in southern Germany and France and were recovered from their tombs.

To a resident of the Mediterranean region, these northern peoples were tall, fair, well built, and with deep resounding voices. But if we were to make such generalizations about any such peoples of the time, we would surely miss the great diversity they must have portrayed. If we were to categorize the Celts, it would be more appropriate to label them as a cultural group, rather then a racial one. The Celts evolved over centuries with mixtures of many different tribes of peoples. Tacitus, a more perceptive observer, distinguished many different types among the Britons, the Scots with reddish hair and long limbs, the Welsh with swarthy faces and curly hair, and those occupying the south-east of the country who more resembled the Gauls. So, the Celts as a whole, differed greatly from the Mediterranean races in their lighter skin color and their greater bulk, they were by no means a homogeneous people.