Ubi's site about Rome, the Eternal City

After that king Tarquinius was driven away by the Romans, the season of the ancient monarchy came to an end.
The first military expansion of Rome was characterized by the Republican phase. The Senate elected two consuls and the religious matters were managed by a priest. The government was in the hand of the nobles -the patricians-, members of the Senate who could also assume public offices.

The plebeians fought in the wars, with bad consequences on the management of their fields and for the craftmanship activities, but they did not participate the division of the conquered lands. After every war, the distance between the classes (or we should better say castes) grew. Plebeians, by increasing their debts, often became slaves.
Hard fights were necessary for the patricians to accept the figure of the tribunus plebis: two magistrates who represented the plebs in the Senate: they could use their veto to reject the laws.
The most important gain for the plebeians were the XII tabula (tablets) laws (engraved in 450 B.C. on bronze boards that were shown in the forum, the most important place in the city). They were the first form of written law emanation, even though another 150 years had to pass before the plebeians could access public offices.

The Roman wars crushed the Etruscans, Volsci, Equis, Sannites; finally Rome grasped the commercial power on the sea with the war agaisnt Taranto and other Greek colonies. Between the 5th and the 3rd century BC, the Romans occupied the whole peninsula, nevertheless, the losers were not enslaved yet forced to accept the laws of Rome and the Latin as language.

Finally, Rome challenged the powerful Carthago (founded by the Phoenicians). The wars against the new enemy lasted more than expected with alterning fortunes; Rome was almost destroyed by the general Annibalis, who reached the Italian peninsula from Spain.
In the end, Rome conquered Spain and the colonies of Carthago, and destroyed the city itself completely, hence the motto DELENDA CARTHAGO.
In that very year (146 B.C.), also Greece became a Roman province.