Celtic warfare
The "Gallic Wars" were a series of military campaigns waged by the Roman proconsul Julius Caesar against Gallic tribes, lasting from 58 BC to 51 BC. The Romans would also raid Britannia and Germania, but these expeditions never developed into full-scale invasions. The Gallic Wars culminated in the decisive Battle of Alesia in 52 BC, in which a complete Roman victory resulted in the expansion of the Roman Republic over the whole of Gaul. The wars paved the way for Caesar to become the sole ruler of the Roman Republic.
Celts
Following the Gallic Wars of 58–51 BC, Caesar's "Celtica" formed the main part of Roman Gaul, becoming the province of Gallia Lugdunensis. This territory of the Celtic tribes was bounded on the south by the Garonne and on the north by the Seine and the Marne. The Romans attached large swathes of this region to neighboring provinces Belgica and Aquitania, particularly under Augustus.