Centuriate Assembly in the context of "Citizens' assemblies of the Roman Republic"

The Senate was the governing and advisory assembly of the aristocracy in the ancient Roman Republic. It was not an elected body, but one whose members were appointed by the consuls, and later by the censors, which were appointed by the aristocratic Centuriate Assembly. After a Roman magistrate served his term in office, it usually was followed with automatic appointment to the Senate. According to the Greek historian Polybius, the principal source on the Constitution of the Roman Republic, the Roman Senate was the predominant branch of government. Polybius noted that it was the consuls (the highest-ranking of the regular magistrates) who led the armies and the civil government in Rome, and it was the Roman assemblies which had the ultimate authority over elections, legislation, and criminal trials. However, since the Senate controlled money, administration, and the details of foreign policy, it had the most control over day-to-day life. The power and authority of the Senate derived from precedent, the high caliber and prestige of the senators, and the Senate's unbroken lineage, which dated back to the founding of the Republic in 509 BC. It developed from the Senate of the Roman Kingdom, and became the Senate of the Roman Empire.

Originally the chief magistrates, the consuls, appointed all new senators. They also had the power to remove individuals from the Senate. Around the year 318 BC, the "Ovinian Plebiscite" (plebiscitum Ovinium) gave this power to another Roman magistrate, the censor, who retained this power until the end of the Roman Republic. This law also required the censors to appoint any newly elected magistrate to the Senate. Thus, after this point in time, election to magisterial office resulted in automatic Senate membership. The appointment was for life, although the censor could impeach any senator.