Celts, a people who dominated much of western and central Europe in the 1st millennium BC, giving their language, customs, and religion to the other peoples of that area.

History
The earliest archaeological evidence associated with the Celts places them in what is now France and western Germany in the late Bronze Age, around 1200 BC. In the early Iron Age, they are associated with the Halstatt culture (8th-6th century BC), named for an archaeological site in Upper Austria. They probably began to settle in the British Isles during this period. Between the 5th and 1st centuries BC, their influence extended from what is now Spain to the shores of the Black Sea. This later Iron Age phase is called La Tène, after a site in Switzerland. The word Celt is derived from Keltoi, the name given to these people by Herodotus and other Greek writers. To the Romans, the Continental Celts were known as Galli, or Gauls; those in Britain were called Britanni. In the 4th century BC, the Celts invaded the Greco-Roman world, conquering northern Italy Macedonia, and Thessaly. They plundered Rome in 390, sacked Delphi in 279, and penetrated Asia Minor, where they were known as Galatians. The “Cisalpine Gauls” of northern Italy were conquered by the Romans in the 2nd century BC; Transalpine Gaul (modern France and the Rhineland) was subdued by Julius Caesar in the 1st century BC, and most of Britain came under Roman rule in the 1st century AD. In the same period, the Celts of central Europe were dominated by the Germanic peoples. In medieval and modern times the Celtic tradition and languages survived in Brittany (in western France), Wales, the Scottish Highlands, and Ireland.

Way of Life
The various Celtic tribes were bound together by common speech, customs, and religion, rather than by any well-defined central governments. The absence of political unity contributed substantially to the extinction of their way of life, making them vulnerable to their enemies. Their economy was pastoral and agricultural, and they had no real urban life. Each tribe was headed by a king and was divided by class into Druids (priests), warrior nobles, and commoners. The nobles fought on foot with swords and spears and were fond of feasting and drinking. Celtic mythology, which included earth gods, various woodland spirits, and sun deities, was particularly rich in elfin demons and tutelaries, beings that still pervade the lore of peoples of Celtic ancestry.

Celtic Christianity
The Christian faith was well established in Celtic Britain by the 4th century AD, but in the 5th century the Saxons and other Germanic peoples invaded the country, driving most of the Celtic Christians into Wales and Cornwall. At the same time, St. Patrick and other British missionaries founded a new church in Ireland, which then became the center of Celtic Christianity. The Irish church developed a distinctive organization in which bishops were subordinate to the abbots of monasteries. The Irish monks, devoted to learning as well as religion, did much to preserve a knowledge of ancient Roman literature in early medieval Europe. Between the late 6th and the early 8th centuries, Irish missionaries were active in Christianizing the Germanic peoples that had conquered the Western Roman Empire, and they founded numerous monasteries in present-day France, Germany, Switzerland, and Italy. Celtic Christianity in Ireland was weakened by the Viking invasions of the 9th and 10th centuries, and by the 12th century its characteristic institutions, which were incompatible with those of the dominant Roman church, had largely disappeared from Europe.

Art
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-6th century 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. The Celtic style is marked by a preference for stylized plant motifs, usually of Greek origin, and fantastic animals, derived from the Scythians and other steppe peoples; the human figure plays a secondary role. Other favorite motifs are elliptical curves and opposing curves, spirals, and chevrons, also derived from steppe art. These elements were combined in dynamic yet balanced, intricate geometrical patterns carried out in relief, engraving, or red, yellow, blue, and green champlevé enamel on shields, swords, sheaths, helmets, bowls, and jewelry. They also appeared on painted pottery cinerary urns, food vessels, incense bowls, and drinking cups. Examples of Celtic art include torcs, or neck rings, with the two open ends ornamented with animal heads; the silver repoussé Gundestorp cauldron (circa 100 BC, National Museum, Copenhagen); a bronze lozenge- shaped shield with circular medallions and small enamel circles (1st century BC-1st century AD); and a bronze mirror with enameled decoration (1st century BC) (both British Museum, London). Also surviving are roughly carved stone monuments and wooden objects. During the period of Roman domination of Western Europe in and after the 1st century BC, the art of Celtic peoples on the Continent gradually lost its distinctive style. The Celts of Ireland continued to work with traditional motifs, but, as Christianity took hold, they combined them with Christian motifs and employed their skills in the service of the church. Their carved stone crosses; intricate metal chalices, bells, and reliquaries; and magnificently illuminated liturgical books may more properly be considered Irish art.