The tribunes of the plebs had been created following the secession of the people in 494 BC. Burdened by crushing debt and angered by a series of clashes between the patricians and plebeians, in which the patricians held all of the political power, the plebeians deserted the city en masse and encamped upon the sacred mount. One of the concessions offered by the senate to end the standoff was the creation of a new office, tribune of the people, for which only plebeians would be eligible. These tribunes had the power to convene the concilium plebis, one of the three major assemblies of the Roman people, and to propose legislation before it; the power to intercede on behalf of a citizen who wished to appeal from the decision of a magistrate; and the power to veto, or block the actions of the senate and magistrates. The tribunes of the plebs were sacrosanct within the boundaries of Rome, and the entire body of the Roman people obliged to protect them from harm. The tribunes thus became the primary check on the power of the senate, as well as the protectors of the rights of the plebeians.
In 473 BC, the tribune Gnaeus Genucius attempted to bring the consuls of the preceding year to trial for having blocked multiple attempts to bring about agrarian reform. But on the morning of the trial he was found to have been murdered in his house, notwithstanding his sacrosanctity. Cowed by the murder of their colleague, the remaining tribunes failed to block a levy of soldiers. Tensions rose as the leaders of the patrician and plebeian factions each argued that the other side was depriving them of their liberty. Things came to a head when Volero Publilius, who had served as a centurion in the Roman army, was called to serve as a common soldier. He refused, and the consuls sent a lictor to arrest him. Publilius resisted, and a scuffle ensued in which the clothes were torn from Publilius' back; breaking free of the lictor, he appealed to the people to defend him. Niebuhr, vol. II, pp. 207–210 (Schmitz, trans.).
At this point, the fury of the mob drove the consuls and their lictors from the forum; the lictors were manhandled, and their fasces broken; the consuls took refuge in the senate house, as the senate deliberated its response. Over the objections of the hard-liners, the senior members prevailed, and took no further actions against the people. For his courage in resisting an unjust order, knowing that it might lead to his death, Publilius became a hero to the people, and was elected one of the tribunes of the plebs for the following year.
As tribune in 472 BC, Publilius surprised the aristocrats, who expected him to foment violence between the classes, by instead choosing a peaceful course of action. He proposed a law transferring the election of the tribunes of the plebs from the comitia centuriata, the oldest of the assemblies, which conferred imperium on magistrates, to the comitia tributa, considered a more democratic assembly. Voting strength in the comitia centuriata was determined by age and property, and the assembly tended to reflect the wishes of the aristocracy, a problem that only increased with the passage of time. Voting in the comitia tributa was done by tribes, with each tribe receiving an equal vote. Although neither the senate nor the consuls favoured the law, they could do nothing to block it. Nonetheless, debate over the law consumed the rest of the year, and the proposal carried over to the following year.
In 471, Publilius and his colleagues continued to press for the passage of his proposal, and raised a second issue. The number of the tribunes of the plebs was not fixed by law; originally two had been appointed following the creation of the office, but they had coöpted two colleagues to serve alongside them, and assist with their duties. The new proposal would officially raise the number of elected tribunes to five. Publilius' colleague, Gaius Laetorius, who had also been a soldier of high reputation, spoke passionately and vociferously in favour of the two laws. But as an unpracticed orator, his rhetoric became inflammatory, and on the day appointed for voting, he and the consul Appius Claudius had a violent confrontation, in which each man attempted to arrest the other. Public sympathy was against Claudius, who was well known as the champion of the aristocracy, and he was hurried out of the forum by his colleague, the moderate Titus Quinctius, who succeeded in calming the crowd.