This period of expansion is known mainly from Roman legends and some archaeological finds. The legends of the founding of Rome include a story of the twin foundling brothers Romulus and Remus selecting different hills as the site for the new city. Competing bird oracles led each of the brothers to assert the location of his wall-building was divinely sponsored. When Remus leaped over Romulus' wall, Romulus killed him.
Romulus had men with him, but they needed wives, so, as legend continues, they held a religious entertainment event to which they invited the neighboring Sabines. At a rehearsed moment, the followers of Romulus kidnapped the young women. Their families went home and stirred up a force to retrieve their daughters, but by the time they returned, the women were pregnant or reconciled and asked their families to get along with their husbands. So the Sabines and Romans were related. From there, the Romans went out to help or conquer other tribes in the Italic peninsula. In time, help and conquest blended and the Romans ran most of the peninsula, although there were areas in the Greek section known as Magna Graecia that waited for the Punic Wars before joining the Roman flock.
1 - Italy - The Growth of Roman Power in Italy
2 - Territorial Expansion of Rome
3 - Northern Africa at the Start of the Second Punic War
4 - Roman Empire 1st Century A.D.
5 - Map of the Extent of the Roman Empire
6 - The Roman Empire about 395
7 - The Roman and Hunnic Empires about 450