The legislative assemblies of the Roman Republic were political institutions in the ancient Roman Republic. According to the contemporary historian Polybius, it was the people who had the final say regarding the election of magistrates, the enactment of Roman laws, the carrying out of capital punishment, the declaration of war and peace, and the creation of alliances. Under the Constitution of the Roman Republic, the people held the ultimate source of sovereignty.

Roman law is the legal system of ancient Rome, including the legal developments spanning over a thousand years of jurisprudence, from the Twelve Tables, to the Corpus Juris Civilis ordered by Eastern Roman emperor Justinian I. Roman law forms the basic framework for civil law, the most widely used legal system today, and the terms are sometimes used synonymously. The historical importance of Roman law is reflected by the continued use of Latin legal terminology in many legal systems influenced by it, including common law.