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 left bank of the Rhine. In English the word Gaul also means one of the inhabitants of that region in ancient times.
The Gauls sacked Rome circa 390 BC, destroying all Roman historical records to that point.
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).
On December 31, 406 the Vandals, Alans and Suebians crossed the Rhine, beginning an invasion of Gallia.
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.