Along with citizenship, the republican government was another important institution of Roman political life. The Romans summed up their political existence in a single phrase: senatus populusque Romanus, “the Senate and the Roman people,” which they abbreviated “SPQR.” This sentiment reflects the republican ideal of shared government rather than power concentrated in a monarchy. It stands for the beliefs, customs, and laws of the republic — its unwritten constitution that evolved over two centuries to meet the demands of the governed.

In the early republic, social divisions determined the shape of politics. Political power was in the hands of a hereditary aristocracy — the patricians, whose privileged legal status was determined by their birth as members of certain families. Patrician men dominated the affairs of state, provided military leadership in time of war, and monopolized knowledge of law and legal procedure. The common people of Rome, the plebeians (plih-BEE-uhns), were free citizens with a voice in politics, but they had few of the patricians’ political and social advantages. While some plebeian merchants rivaled the patricians in wealth, most plebeians were poor artisans, small farmers, and landless urban dwellers.

The Romans created several assemblies through which men elected high officials and passed ordinances. The most important of these was the Senate, a political assembly that by tradition was established by Romulus and in reality most likely originated in the monarchical period as a council of the heads of powerful families who advised the king. During the republic, the Senate advised the consuls and other officials about military and political matters and handled government finances. Because the Senate sat year after year with the same members, while the consuls changed annually, it provided stability, and its advice came to have the force of law. Another responsibility of the Senate was to handle relations between Rome and other powers, as Polybius, a Greek politician and historian writing in the middle of the second century B.C.E., reported:

If it is necessary to send an embassy to reconcile warring communities, or to remind them of their duty, or sometimes to impose requisitions upon them, or to receive their submission, or finally to proclaim war against them — this too is the business of the Senate.1

The highest officials of the republic were the two consuls, positions initially open only to patrician men. The consuls commanded the army in battle, administered state business, and supervised financial affairs. When the consuls were away from Rome, praetors (PREE-tuhrz) could act in their place; they could also command armies, interpret law, and administer justice. After the age of overseas conquests (see ”Overseas Conquests and the Punic Wars, 264–133 B.C.E.”), the Romans divided their lands in the Mediterranean into provinces governed by ex-consuls and ex-praetors. Because of these officials’ experience in Roman politics, they were suited to administer the affairs of the provinces and to adapt Roman law and customs to new contexts. Other officials worked with the Senate to oversee the public treasury, register citizens, and supervise the city of Rome.

A lasting achievement of the Romans was their development of law. Roman civil law, the ius civile, consisted of statutes, customs, and forms of procedure that regulated the lives of citizens. As the Romans came into more frequent contact with foreigners, the praetors applied a broader ius gentium, the “law of the peoples,” to such matters as peace treaties, the treatment of prisoners of war, and the exchange of diplomats. In the ius gentium, all sides were to be treated the same regardless of their nationality. By the late republic, Roman jurists had widened this still further into the concept of ius naturale, “natural law” based in part on Stoic beliefs (see “Philosophy and Its Guidance for Life” in Chapter 5). Natural law, according to these thinkers, is made up of rules that govern human behavior that come from applying reason rather than customs or traditions, and so apply to all societies. In reality, Roman officials generally interpreted the law to the advantage of Rome, of course, at least to the extent that the strength of Roman armies allowed them to enforce it. But Roman law came to be seen as one of Rome’s most important legacies.