Gauls (c-500 - c500). The Gauls were a group of Celtic peoples of Western Europe in the Iron Age and the Roman period. The area they inhabited was known as Gaul. Their Gaulish language forms the main branch of the Continental Celtic languages. The Gauls emerged around the 5th century BC as the bearers of the La Tène culture north of the Alps. By the 4th century BC, they spread over much of what is now France, Belgium, The Netherlands, Spain, Portugal, Switzerland, Southern Germany, Austria, the Czech Republic and Slovakia by virtue of controlling the trade routes along the river systems of the Rhône, Seine, Rhine, and Danube, and they quickly expanded into Northern Italy, the Balkans, Transylvania and Galatia. Gaul was never united under a single ruler or government, but the Gallic tribes were capable of uniting their forces in large-scale military operations. They reached the peak of their power in the early 3rd century BC.The rising Roman Republic after the end of the First Punic War increasingly put pressure on the Gallic sphere of influence; the Battle of Telamon of 225 BC heralded a gradual decline of Gallic power over the 2nd century, until the eventual conquest of Gaul in the Gallic Wars of the 50s BC. After this, Gaul became a province of the Roman Empire, and the Gauls culturally adapted to the Roman world, bringing about the formation of the hybrid Gallo-Roman culture. The Gauls of Gallia Celtica according to the testimony of Caesar called themselves Celtae in their own language, and Galli in Latin.As is not unusual with ancient ethnonyms, these names came to be applied more widely than their original sense, Celtae being the origin of the term Celts itself while Galli is the origin of the adjective Gallic, now referring to all of Gaul. Hallstatt culture and La Tène culture Gaulish culture developed out of the Celtic cultures over the first millennium BC. The Urnfield culture represents the Celts as a distinct cultural branch of the Indo-European-speaking people. The spread of iron working led to the Hallstatt culture in the 8th century BC; the Proto-Celtic may have been spoken around this time. The Hallstatt culture evolved into the La Tène culture in around the 5th century BC. The Greek and Etruscan civilizations and colonies began to influence the Gauls especially in the Mediterranean area.Gauls under Brennus invaded Rome circa 390 BC. By the 5th century BC, the tribes later called Gauls had migrated from Central France to the Mediterranean coast. Gallic invaders settled the Po Valley in the 4th century BC, defeated Roman forces in a battle under Brennus in 390 BC and raided Italy as far as Sicily. In the 3rd century BC, the Gauls attempted an eastward expansion in 281-279 BC, towards the Balkan peninsula, which at that time was a Greek province, with the ultimate goal to reach and loot the rich Greek city-states of the Greek mainland, but the majority of the Gaul army was exterminated by the Greeks and the few Gauls that survived were forced to flee. A large number of Gauls served in the armies of Carthage during the Punic Wars, and one of the leading rebel leaders of the Mercenary War, Autaritus, was of Gallic origin. Main article: Gallic invasion of the Balkans During the Balkan expedition, led by Cerethrios, Brennos and Bolgios, the Gauls raided twice the Greek mainland. At the end of the second expedition the Gallic raiders had been repelled by the coalition armies of the various Greek city-states and were forced to retreat to Illyria and Thrace, but the Greeks were forced to grant safe-passage to the Gauls who then made their way to Asia Minor and settled in Central Anatolia. The Gallic area of settlement in Asia Minor was called Galatia; there they created widespread havoc. But they were checked through the use of war elephants and skirmishers by the Greek Seleucid king Antiochus I in 275 BC, after which they served as mercenaries across the whole Hellenistic Eastern Mediterranean, including Ptolemaic Egypt, where they, under Ptolemy II Philadelphus, attempted to seize control of the kingdom. In the first Gallic invasion of Greece, they achieved victory over the Macedonians and killed the Macedonian king Ptolemy Keraunos. They then focused on looting the rich Macedonian countryside, but avoided the heavily fortified cities. The Macedonian general Sosthenes assembled an army, defeated Bolgius and repelled the invading Gauls.