HIERARCHY

Rome was ruled by kinas, who were elected from each of Rome's major tribes in turn, in military matters, the king's authority (Imperium) was likely absolute. He was also the head of the state religion. In addition to the authority of the King, there were three administrative assemblies, the Senate, the Comitia Curiata and the Comitia Calata.
Roman laws traditionally could only be passed by a vote of the Popular assembly, However, the Roman Senate represented an oligarchic institution, which acted as an advisory body. In the Republic, the Senate held great authority but no actual legislative power; it was technically only an advisory council.