The character of the tribunes was, in every respect, different from that of the consuls. The appearance of the former was modest and humble; but their persons were sacred and inviolable. Their force was suited rather for opposition than for action. They were instituted to defend the oppressed, to pardon offences, to arraign the enemies of the people, and, when they judged it necessary, to stop, by a single word, the whole machine of government.

The History of the Decline and Fall of the Roman Empire - Volume the First (ed. 1776)