Where and how did Roman civilizations develop?

There was only one Roman civilisation. It arose from the culture of the Romans (who were the inhabitansts of the city of Rome) and the Latins (the Romans were Latins) in central Italy. In the early days there were influences from the Sabines, the Etruscans and the Greek colonies (settlements) in southern Italy and Sicily. Later there was also influence from the Greeks of mainland Greece.