Roman Republic was the phase of the ancient Roman civilization characterized by a republican form of government; a period which began with the overthrow of the Roman monarchy, c. 509 BC, and lasted over 450 years until its subversion, through a series of civil wars, into the Principate form of government and the Imperial period.

According to Livy the Senate, initially consisting of 100 men, was created by Rome's first king, Romulus

no meeting could take place more than a mile outside of the pomerium

The first emperor, Augustus, reduced the size of the senate from 900 members to 600