What is the social structure in Rome?

Slaves at the bottom, then freedmen, and free-born citizens at the top. Then the free-born citizens were divided up into the Patricians and the Plebeians. The Patricians could trace their ancestry to one of the 100 Patriarchs at the founding of the city and the Plebeians, or Plebs, could not. Mostly, the Plebs were the common-folk, but that does not mean they could not be rich.