This article is part of theHistory of France series.
Gallia (in English Gaul) is the Roman name for the region of western Europe occupied by present-day France, Belgium, western Switzerland and the parts of the Netherlands and Germany on the west bank of the Rhine river. In English the word Gaul commonly refers to a Celtic inhabitant of that region in ancient times.
But the Gauls were widespread in Europe by Roman times, speaking Celtic languages that had diverged into two groups. Besides the Gauls of modern-day France, Gauls had settled in the plains of northern Italy, in the province Romans knew as Gallia Cisalpina ("Gaul this side of the Alps'). Other Gauls had migrated across the Pyrenees into Spain, where they mixed with the indigenous Iberians as "Galloiberians.'
In the Aegean world, a huge migration of Eastern Gauls appeared in Thrace, north of Greece, in 281 BC. Another Gaulish chieftain named Brennus, at the head of a large army, was only turned back from desecrating the Temple of Apollo at Delphi at the last minute, alarmed, it was said, by portents of thunder and lightning. At the same time a migrating band of Celts, some 10,000 fighting men, with their women and children and slaves, were moving through Thrace. Three tribes of Gauls crossed over from Thrace to Asia Minor at express invitation of Nicomedes I of Bithynia, who required help in a dynastic struggle against his brother. Eventually they settled down in eastern Phrygia and Cappadocia in central Anatolia, in a region henceforth known as Galatia.
Roman rule in Gaul was established by Julius Caesar, who defeated the Celtic tribes in Gaul 58-51 BC and described his experiences in De Bello Gallico, which means Of the Gallic War. The war cost the lives of more than a million Gauls, and a million further were enslaved.
The area was subsequently governed as a number of provinces, the principal ones being Gallia Narbonensis, Gallia Lugdunensis, Gallia Aquitania and Gallia Belgica. The capital of the Gauls was Lyon (Lugdunum).
After coming under increasing pressure from the tribes of Germany from the middle of the 3rd century AD, Roman rule in Gaul ended with the defeat of the Roman governor Syagrius by the Franks in AD 486.
In the 6th century, the former Gaul continued to be divided in three parts, as Caesar had described. The Franks were in occupation of most of the territory. A Visigothic kingdom was established in the southwest region that would become Aquitaine. And in the areas that would become Provence and Languedoc a Gallo-Roman culture continued into the time of Gregory of Tours.