The Etruscans were the dominant influence in the area, and contributed heavily to Roman Civilization. Among their contributions:
They were the first to use the Arch for building bridges. It is a form that adds strength, and dissipates the weight of a structure. It is from the Arch that we get our word “architecture.” They also introduced soothsayers, and gods with human forms, mostly borrowed from the Greeks, of course. They held slave fights – typically at funerals, as a blood memorial to one’s greatness. These were the forerunner of the Gladiatorial games. They also started public parades as welcomes for War heroes. Finally, they adopted the Greek alphabet; somewhat altered, but in use still today. By and large, the Etruscans probably contributed more than the Greeks, as much of the culture we consider "Roman" originated with the Etruscans.