The tribunes

As was mentioned in chapter 2, the tribunate was introduced in 494 BC as an exclusively plebeian office. At first two tribunes were appointed, but their number was subsequently increased to five and, around the middle of the fifth century BC, to ten.

The tribunes were not regarded as magistrates (they acted as representatives of the plebeians only) and, unlike the regular magistrates, had neither imperium nor ordinary potestas. Yet they exercised such wide powers (tribunicia potestas) that their decisions had a strong impact on the affairs of the whole community. They had the right to intervene on behalf of any member of the plebeian class who sought their assistance (auxilium) and could invalidate acts of magistrates by simply pronouncing the word intercede or veto (I forbid).^[298] By exercising their right of veto against magistrates presiding over meetings of the senate and the assemblies they could prevent these bodies from functioning. Although they did not possess the ius vocationis, i.e. the right of summoning citizens to appear before them, they could order the arrest and prosecution of any person who, in their presence, encroached upon the rights of the plebeians (ius pre hens ionis).^iM Moreover, they had the right to convene and preside over the assembly of the plebeians (concilium plebis) and, in later years, the assembly of the tribes (comitia tributa), and to submit laws to them (leges tribuniciae).

However, the power of the tribunes was not free from limitations. Not only did they lack imperium, and hence the ability to command an army, but their civil powers as well as their independence from consular control did not extend outside the city limits.¹⁰ A further restriction on the tribunician power resulted from the right of the tribunes to block by veto each other's acts. Moreover, the granting of assistance (auxilium) to a citizen by a tribune was conditional upon the consent of his colleagues. This took the form of a public declaration (decretum) made by one of the tribunes on behalf of all (pro coliegio sententia pronuntiare). Further restrictions on the tribunes' power were imposed in times of emergency, when the government of the state was put into the hands of a dictator, or by special legislation.

On many occasions, especially during the later Republic, the tribunes' power of veto played in the hands of members of the senatorial aristocracy who, by winning over one or more tribunes and inducing them to use their prohibitio or intercessio against the rest, frustrated legislative initiatives they regarded as detrimental to their interests.^[299] [300] [301] [302] In the closing years of the Republic the tribunate lost much of its earlier prestige as many of its holders became mere organs in the hands of political factions and military leaders fighting for political supremacy. After the fall of the Republic the office was used as one of the chief instruments by which Augustus and his successors sought to secure their power.