The "Tribuni Plebis", known in English as "Tribunes of the Plebs, Tribunes of the People," or "Plebeian Tribunes," were instituted in 494 BC, after the first secession of the plebs, in order to protect the interests of the plebeians against the actions of the senate and the annual magistrates, who were uniformly patrician. 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.