This study will be the first about the Roman tribunate of the plebs that spans its entire history in the Republic and Empire chronologically since Niccolini’s 1932 Il tribunato della plebe. All available sources will be analysed and the literature on the subject that appeared in various contributions since 1932 integrated into one body. Beginning with an attempt to trace the earliest antecedents of the tribunate to the time of the Roman kings, the study follows the development of the tribunate from a revolutionary agency of opposition through the gradual acceptance of its presence by the patricians and its incorporation as a state magistracy. By an investigation of the activities of the tribunes an attempt is made to trace the origins of the various powers they could claim. It will be shown how the tribunes acted as the mouthpiece of the common people by means of plebiscita and as safeguards of a just military levy in a society that was constantly going to war, and in which capacity they laid claim to extensive prerogatives concerning the regulation of military matters and foreign policy, plebeian integration, as well as an punitive authority over those generals who did not do well in the field. The powers and the authority vested in the office by the lex Hortensia, which removed the need for senatorial approval for plebiscita to become law, will be investigated to determine if the tribunes were the main legislators of mid-republican Rome, with the ability to make use of a fully developed right to veto any legislation or block any public business they deemed contrary to the interests of the people. Their judiciary powers also will be considered as they had developed into a role of state prosecutors for the tribunes, who were looked upon as watchdogs over the Roman constitution and safe keepers of the old ways of the republic. A different approach will be presented about tribunes attempting reforms in the wake of the Gracchi, who met with and resorted to violence to ensure their measures were passed, thus igniting the chain of events that had the end of the republic as its result. The study will continue to follow the trace of the tribunate after tribunician powers were conferred on Caesar, which established a precedent for his political heir, who used the tribunicia potestas as the pillar of his position at the head of the Roman Empire and the designation of his successor. The work ends with the last mention of a plebeian tribune, in the year 423 AD.