During the Celtic Iron Age (c. 800-15 BCE), the Celts dominated large swaths of the European continent including what is present-day Germany, Switzerland, and France.
The ancient Celts were various population groups living in several parts of Europe north of the Mediterranean region from the Late Bronze Age onwards. Given the name Celt by ancient writers, these tribes often migrated and so eventually occupied territories from Portugal to Turkey. Although diverse tribes the ancient Celts spoke the same language and maintained the same artistic tradition which is characterised by the use of idiosyncratic flowing lines and forms. Celtic languages are still spoken today in parts of the British Isles and northern France.
Ancient writers gave the name Celts to various population groups living across central Europe inland from the Mediterranean coastal areas. Most scholars agree that the Celtic culture first appeared in the Late Bronze Age in the area of the upper Danube sometime around the 13th century BCE. These early Celts were known as the ‘Urnfield people’ and they probably spoke a proto-Celtic language. By the 8th century BCE, iron had replaced bronze-working and the cultural group is then referred to by scholars as the ‘Hallstatt culture’. Spain saw a similar development with tribes using iron weapons. The Hallstatt culture declined by the 5th century BCE, perhaps due to internal political tensions and economic difficulties. The next phase of Celtic development was carried out by a group known as the La Tène culture.
The migration of various Celtic tribes in order to flee wars meant that eventually they occupied Territory from the Iberian peninsula to Turkey. The prosperity of the La Tène culture in ancient France, Spain and wider central Europe meant that they were able to challenge the contemporary Mediterranean cultures and so they appear for the first time in Classical history. From then on these peoples were widely referred to as Celts. In antiquity writers did not describe tribes in ancient Britain and Ireland as Celts, although they have acquired that label in modern times and some Celtic languages or their derivatives are still spoken there, as a form of Celtic still is in the Brittany region of northern France. The religion of the Celts, led by a priesthood known as the Druids, is described by ancient writers with some disdain as crude and violent.
The migration of various Celtic tribes in order to flee wars – they were famously attacked in Gaul by Julius Caesar in the 1st century BCE and by the Germanic tribes – and find new prospects meant that eventually the territory occupied by them ranged from Galicia (the Iberian peninsula) to Romania. Many Celtic tribes spread eastwards, for example, traversing Macedonia in 280 BCE and crossing the Hellespont in 278 BCE into Asia Minor. The Galatians, as they were now called, colonised areas of central Asia Minor which brought them into direct conflict with both the Hellenistic kingdoms and Rome.
Celtic armies first came to the attention of historians when the Gauls, led by their king Bran (Brennus), sacked Rome in 390 BCE, and again in 279 BCE when they looted Delphi as they passed through Greece on their way to Asia. The Celts attacked the Romans again in 225 BCE and were frequent mercenary allies of Carthage during the Punic Wars. The Celts thus gained a reputation with Latin and Greek writers for being fierce warriors and skilled horsemen who also fielded chariots in battle. Julius Caesar faced them when he invaded Gaul. They were light, pulled by two horses, and had an open front and back with double hoops at the sides. Containing two men they were used to attack enemy cavalry first by throwing javelins and then one man dismounted to fight on foot while the rider drove the chariot to a safe distance to await a retreat if necessary. Caesar describes them as driven with great skill and so were a highly manoeuvrable weapon of disruption and attack.
Celtic warriors were known for their long hair and imposing physique. They are depicted in Greek art with their distinctive long shields (wooden panels covered in decorated hide) and long swords. Such was the respect for Celtic warriors that Hellenistic kings who defeated Galatian armies were given the title of soter, meaning ‘saviour’. Although Galatian armies were almost always defeated by their more disciplined and better-equipped enemies in single battles, once conquered, they did fight successfully as mercenaries in many Hellenistic and Roman armies.
The Celtic language is a branch of the Indo-European language family. Scholars have divided Celtic languages into two groups: Insular Celtic and Continental Celtic. The latter group was no longer widely spoken after the Roman imperial period, and the only surviving examples of it are mentions in the works of Greek and Roman writers and some epigraphic remains such as pottery graffiti and votive and funerary stelae. The best documented of this group is Gaulish.
The Insular Celtic group of languages are two: British or Brittonic (Breton, Cornish, and Welsh) and Goidelic (Irish and its medieval derivatives, Scots Gaelic and Manx). Brittonic was spoken in all of Britain in the Roman period. From it evolved Cumbrian (extinct since medieval times), Cornish (no longer spoken after the 18th century CE but recently revived), Breton (likely introduced by 5th-century CE British settlers and not connected directly to Gaulish), and Welsh, which is still spoken today. The earliest evidence of Goidelic-Irish dates to the 5th century CE, and it later evolved into Middle Irish (c. 950 – 1200 CE) and, thereafter, morphed again into Modern Irish, which is still spoken today.