Rome grew in an ad hoc way, meaning it wasn’t planned all at once but grew over time since the 8th century. However, Romans structured their cities in a very methodical way based on military strategy and planning. In this way, they built camps that were laid out in a geometric plan, usually square or rectangular. That’s why ideal Roman cities are called military camp design. Roman political institutions reflected Roman society, which was divided into two classes: the patricians, wealthy elites, and the plebeians, the common people. Initially, only the patricians were able to hold political office and make important decisions. For example, plebeians could not join the Roman Senate—an advisory body unable to create laws on its own but whose recommendations were taken seriously by the consuls. To become a senator, a Roman had to have held a political office, and plebeians could not. Over time, however, the plebeians were able to gain more influence in the political system.