Battle of Alesia
Caesar engaged in the Gallic Wars (58–50 BC), which led to his conquest of Gaul beyond Gallia Narbonensis. When the Helvetii, a federation of tribes from what is now Switzerland, planned a migration to the Atlantic coast through Gaul, Caesar went to Geneva and forbade the Helvetii to move into Gaul. While he went to Gallia Cisalpina to collect three other legions, the Helvetii attacked the territories of the Aedui, Ambarri, and Allobroges, three Gallic tribes, which called for Caesar’s help. Caesar and his Gallic allies defeated the Helvetii. The Gallic tribes then asked for Caesar to intervene against an invasion by the Suebi, a Germanic tribe. Caesar defeated the Suebi. In 57 BC he intervened in intra-Gallic conflicts and marched on the Belgae of northern Gaul. From then on he conquered the Gallic peoples one by one. His successes in Gaul brought Caesar political prestige in Rome and great wealth through the spoils of wars and the sale of war captives as slaves.
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.