High Quality Content by WIKIPEDIA articles! 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 (and thus the assemblies) who had the final say regarding the election of magistrates, the enactment of new statutes, the carrying out of capital punishment, the declaration of war and peace, and the creation (or dissolution) of alliances. Under the Constitution of the Roman Republic, the people (and thus the assemblies) held the ultimate source of sovereignty.