The title of one of the offices of the
Roman Republic. There were 10 Tribuni Plebis, or "Tribunes of the People," and they were elected every year.
They could present laws to the Gathering of the Plebs, and pass them. They could veto one another and any other official in the Republic (including the Consul). No other official could veto their actions.
The Tribuni had 'Sacro Sanctitas', which meant that any one who touched the body or the hair of a Tribunus with ill intent was immediately executed, regardless of his position.
The Tribuni were considered the protectors of the plebs and only one of the plebs could be elected to this position.