The name Celt originated with the ancient Greeks, who called the barbarian peoples of central Europe Keltoi. Rather that being a broad cultural genetic 'race,' the Celts were a broad cultural-linguistic group. The area where they lived became a constantly changing collection of tribal 'nations.' The Celts were never an 'empire' ruled by one government.
The ancestors of the Celts were the people of the Urnfield culture, so-called because they buried their dead in cremation urns in flat ground. Between 1200 and 700 BC, they spread westward from their eastern European homeland into the area of modern Austria, Germany, Switzerland, and France. Here, there culture developed into a recognizably Celtic form. The earliest stage of Celtic culture is called the Hallstatt, after a village in the Austrian Salzkammergut where archeologists discovered important artifacts. At hallstatt and other places with the 'hall' (salt) name - Hallein, Helle, Schwabisch Hall - the Celts' wealth was based upon salt extraction and sale. The technology of iron, too, was embraced by innovative Celtic blacksmiths, who produced the best metal in Europe, that was in great demand outside Celtic Areas. An important two-way trade developed between the Celts and the Greeks, both in their homeland, and their colonies inwhat is now southern France.
By the seventh century BC, the Hallstatt people had become prosperous in the salt and iron businesses. In around 650 BC, the Celts began to re-exchange raids with the Greeks and Etruscans, elements of whose culture they adopted. By adding and adapting Graeco-Etruscan elements to the Hallstatt culture, the characteristically Celtic style of art came into being. As a result of this, in northeastern France, Switzerland, and the middle Rhine, a new stage of Celtic development took place.
Archeologists call it the early La Tene period, after the definitive artifacts found at La Tene, on Lake Neuchatel in Switzerland. During the Classical period of Greece and Rome, Celtic culture was predominant north of the Alps. Celtic technicians of the La Tene period were technically superior to their Greek and Roman counterparts. Their superior weaponry, including a new type of sword, chain mail, and chariots, enabled the Celts to mount miliatary expiditions against neighboring tribes and nations, including the Greeks and Romans. Celtic fighting men had such a good reputation that they were in great demand as mercenareis. The warrior culture was at the heart of Celtic society, as the heroic sagas of ancient Ireland record.