Rome would conquer the Hellenistic states in 27 BCE. They also conquer Germania, which is basically Western Europe. After a time they received some real push back.
...In 450 B.C., (click here) the first Roman law code was inscribed on 12 bronze tablets–known as the Twelve Tables–and publicly displayed in the Roman Forum. These laws included issues of legal procedure, civil rights and property rights and provided the basis for all future Roman civil law. By around 300 B.C., real political power in Rome was centered in the Senate, which at the time included only members of patrician and wealthy plebeian families....
But, here in a parallel universe, Rome was developing very similar governance as the Greeks. They were also extremely racist. The only governing was conducted by Roman men. Not only did the Roman men only govern, but, they only married Roman women. The exception was the outrage of Rome when Ceasar brought Cleopatra back to the city and provided her residence within it. Julius Ceasar was eventually murdered.
The thing to remember is that while unrelated in the beginning of their governance, both, the Romans and the Greeks found a democracy of one kind of another.
The Roman governance is considered a Republic and different because there was a ruling class that governed by votes, but, the masses did not have a vote. Also different than the Greeks, Rome maintained control over the empire until Eastern Rome or the city of Constantinople became more powerful than Rome, Italy.
There was far less equality than in Greece and conquest was necessary to bring wealth and comfort to Roman citizens. There were Roman city/states, however, their local authority was limited and had to answer to Rome. They collected taxes from the local people to pay to Rome, too.
