The Tribunus Plebis, or Tribune of the Plebs, was a significant elected official in ancient Rome who represented the interests of the plebeians, the common people. This position was established in 494 BCE to provide a political voice and safeguard the rights of the lower class against the patrician class's dominance. The tribune had the power to veto legislation and protect plebeians from arbitrary actions by magistrates, playing a crucial role in the development of Roman political dynamics.