In 387 BCE, Rome was sacked by an invading Gallic army, a humiliation which proved a catalyst for subsequent campaigns, which would end in Roman dominance of the Italian peninsula. The Latin League, an alliance of city states centred upon Aricia, had refused to help Rome against the Gauls and were first forced to accept Rome’s leadership before being annexed after the Latin War (341–338 BCE), while Etruria had used the Gallic invasion as an opportunity to seize some border towns from Rome. Rome repaid the Etruscans with a series of conflicts which would culminate in Rome’s final victory in the Battle of Lake Vadimo in 283 BCE and the annexation of the last Etruscan territory by around 264 BCE. Rome’s most redoubtable opponents of this period were the Samnites, whose strongholds were in the Apennine mountains. After three wars, Rome would finally subdue the Samnites in 290 BCE, having earlier secured the allegiance of the Aequi and Marsi, former Samnite allies.
— OR —