The Roman-Gallic Wars were a series of conflicts between the forces of ancient Rome and various groups identified as Gauls. Among these were the Senones, Insubres, Boii and Gaesatae. Broadly, the Gauls crossed the Alps from Transalpine Gaul into Cisalpine Gaul and tried to expand south through Etruria toward Rome. After centuries, Rome was victorious in Italy and took the battle across the Alps into Transalpine Gaul.
Cisalpine
Major conflicts on the Italian side of the Alps include: 390 BC: Brennus leads the Senones to Clusium in Etruria. Rome sends an army to drive the Senones away, which the Senones defeat at the Battle of the Allia. Brennus leads his men on to besiege Rome. 302 BC: Gauls cross the Alps into Transalpine Gaul, where Gallic tribes allow them to passsouthward and some join the march. They pillage Roman territory and retire with the loot, but then fall to fighting among themselves. 298-290 BC: The Third Samnite War. An alliance of Samnites, Gauls, Etruscans and Umbrians fights Rome. 284 BC: The Gauls besiege Arretium. The Romans march to relieve the city, and the Gauls defeat them. Rome then sends a punitive expedition north which defeats the Senones and drives them out of their territory, which Rome occupies. Then in 283 BC the Boii, with Etruscan allies, march on Rome. Rome is victorious at the Battle of Lake Vadimo. 225 BC: The Insubres and Boii hire Alpine Gauls, the Gaesatae, to join them and march on Rome. The Gauls defeated the Romans at Faesulae, but later the Romans defeated the Gauls at Telamon. 223-193 BC: After this came a concerted Roman policy aimed at conquering Gallic territories south of the Alps. Rome invaded the territory of the Insubres in 223 BC, and took Clastidium, Acerrae and Mediolanum in 222 BC. Rome fought Carthage in the Second Punic War, and the Gauls typically sided with Carthage. After the war, Rome took Bononia, Placentia and Mutina. After this, many of the surviving Boii retreated north across the Alps to form a new state, Boihaemum.
