the tribunes would be outlawed, and the whole body of the plebeians entitled to kill such person without fear of penalty. The senate agreeing to these terms, the people returned to the city. The first tribuni plebis were Lucius Albinius Paterculus and Gaius Licinius, appointed for the year 493 BC. Soon afterward, the tribunes themselves appointed Sicinius and two others as their colleagues. The ancient sources indicate the tribunes may have originally been two or five in number. If the former, the college of tribunes was expanded to five in 470 BC. Either way, the college was increased to ten in 457 BC, and remained at this number throughout Roman history. They were assisted by two aediles plebis, or plebeian aediles. Only plebeians were eligible for these offices, although there were at least two exceptions. Powers of the tribunes Although sometimes referred to as plebeian magistrates, the tribunes of the people, like the plebeian aediles, who were created at the same time, were technically not magistrates, as they were elected by the plebeian assembly alone. However, they functioned very much like magistrates of the Roman state. They could convene the concilium plebis, which was entitled to pass legislation affecting the plebeians alone (plebiscita), and beginning in 493 BC to elect the plebeian tribunes and aediles. From the institution of the tribunate, any one of the tribunes of the plebs was entitled to preside over this assembly. The tribunes were entitled to propose legislation before the assembly. By the third century BC, the tribunes also had the right to call the senate to order, and lay proposals before it. Ius intercessionis, also called intercessio, the power of the tribunes to intercede on behalf of the plebeians and veto the actions of the magistrates, was unique in Roman history. Because they were not technically magistrates, and thus possessed no maior potestas, they relied on their sacrosanctity to obstruct actions unfavourable to the plebeians. Being sacrosanct, no person could harm the tribunes or interfere with their activities. To do so, or to disregard the veto of a tribune, was punishable by death, and the tribunes could order the death of persons who violated their sacrosanctity. This could be used as a protection when a tribune needed to arrest someone. This sacrosanctity also made the tribunes independent of all magistrates; no magistrate could veto the action of a tribune. If a magistrate, the senate,