The Roman Republic
The Roman Republic was founded in 509 BCE and lasted for almost 500 years. The pillars of the republic were the consuls and magistrates, the Senate, and the Popular Assemblies.
Two leaders (called consuls) were elected by the Senate, and they served for one year each. Each consul could veto acts of the other. They were responsible for the conduct of war, finances, and the judiciary. Although powerful, the consuls governed with the advice of the Senate. The magistrates served as public officials in the executive branch of the government and were elected to terms with defined limits.
The Senate consisted of heads of clans and former consuls, and members served for life. Besides electing and advising consuls, the Senate's role was to enact "decrees of the Senate." These decrees did not have formal authority but were often considered in legal cases.
The common people also formed the Popular Assemblies, where they approved laws proposed by magistrates. The common people in the assemblies voted for tribunes who had the power to support or reject laws, senatorial decrees, and election results. Tribunes served one-year terms.
