The Roman conquest of Italy was the result of a series of conflicts in which the city-state of Rome grew from being the dominant state in Latium to become the ruler of all of Italy.The first major Roman conquest in historical times came with the final defeat of her neighbour Veii in 396 BC.In the second half of the 4th century BC Rome clashed repeatedly with the Samnites, a powerful tribal coalition. By the end of these wars Rome had become the most powerful state in Italy.The last threat to Roman hegemony came when Tarentum enlisted the aid of Pyrrhus of Epirus during the Pyrrhic War (282 - 272 BC).he first major Roman conquest in historical times came with the final defeat of her neighbour Veii in 396 BC. In the second half of the 4th century BC Rome clashed repeatedly with the Samnites, a powerful tribal coalition. By the end of these wars Rome had become the most powerful state in Italy.