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.
Battle of the Catalaunian Plains
The Battle of the Catalaunian Plains (or Fields), also called the Battle of the Campus Mauriacus, Battle of Châlons, Battle of Troyes or the Battle of Maurica, took place on June 20, 451 AD, between a coalition led by the Roman general Flavius Aetius and the Visigothic king Theodoric I against the Huns and their vassals commanded by their king Attila. It was one of the last major military operations of the Western Roman Empire, although Germanic foederati composed the majority of the coalition army. Whether the battle was strategically conclusive is disputed: the Romans possibly stopped the Huns' attempt to establish vassals in Roman Gaul. However, the Huns successfully looted and pillaged much of Gaul and crippled the military capacity of the Romans and Visigoths. The Hunnic Empire was later dismantled by a coalition of their Germanic vassals at the Battle of Nedao in 454.