It was in this latter way that the monarchy was terminated in Rome. For however much the history of the expulsion of the last Tarquinius, "the proud", may have been interwoven with anecdotes and spun out into a romance, it is not in its leading outlines to be called in question. Tradition credibly enough indicates as the causes of the revolt, that the king neglected to consult the senate and to complete its numbers; that he pronounced sentences of capital punishment and confiscation without advising with his counsellors; that he accumulated immense stores of grain in his granaries, and exacted from the burgesses military labour and task-work beyond what was due. The exasperation of the people is attested by the formal vow which they made man by man for themselves and for their posterity that thenceforth they would never tolerate a king; by the blind hatred with which the name of king was ever afterwards regarded in Rome; and above all by the enactment that the "king for offering sacrifice" (rex sacrorum or sacrificulus) - whom they considered it their duty to create that the gods might not miss their accustomed mediator - should be disqualified from holding any further office, so that this man became the foremost indeed, but also the most powerless in the Roman commonwealth. Along with the last king all the members of his clan were banished - a proof how close at that time gentile ties still were. The Tarquinii thereupon transferred themselves to Caere, perhaps their ancient home[1], where their family tomb has recently been discovered. In the room of the one president holding office for life two annual rulers were now placed at the head of the Roman community. This is all that can be looked upon as historically certain in reference to this important event[2]. It is conceivable that in a great community with extensive dominion like the Roman the royal power, particularly if it had been in the same family for several generations, would be more capable of resistance, and the struggle would thus be keener, than in the smaller states; but there is no certain indication of any interference by foreign states in the struggle. The great war with Etruria - which possibly, moreover, has been placed so close upon the expulsion of the Tarquins only in consequence of chronological confusion in the Roman annals - cannot be regarded as an intervention of Etruria in favour of a countryman who had been injured in Rome, for the very sufficient reason that the Etruscans notwithstanding their complete victory neither restored the Roman monarchy, nor even brought back the Tarquinian family.

If we are left in ignorance of the historical connections of this important event, we are fortunately in possession of clearer light as to the nature of the change which was made in the constitution. The royal power was by no means abolished, as is shown by the very fact that, when a vacancy occurred afterwards as before, an "interim king" (interrex) was nominated. The one life-king was simply replaced by two year-kings, who called themselves generals (praetores), or judges (iudices), or merely colleagues (consules)[3]. The principles of collegiate tenure and of annual duration are those which distinguish the republic from the monarchy, and they first meet us here.

The collegiate principle, from which the third and subsequently most current name of the annual kings was derived, assumed in their case an altogether peculiar form. The supreme power was not entrusted to the two magistrates conjointly, but each consul possessed and exercised it for himself as fully and wholly as it had been possessed and exercised by the king. This was carried so far that, instead of one of the two colleagues undertaking perhaps the administration of justice, and the other the command of the army, they both administered justice simultaneously in the city just as they both set out together to the army; in case of collision the matter was decided by a rotation measured by months or days.  A certain partition of functions withal, at least in the supreme military command, might doubtless take place from the outset - the one consul for example taking the field against the Aequi, and the other against the Volsci - but it had in no wise binding force, and each of the colleagues was legally at liberty to interfere at any time in the province of the other. When, therefore, supreme power confronted supreme power and the one colleague forbade what the other enjoined, the consular commands neutralized each other. This peculiarly Latin, if not peculiarly Roman, institution of co-ordinate supreme authorities - which in the Roman commonwealth on the whole approved itself as practicable, but to which it will be difficult to find a parallel in any other considerable state - manifestly sprang out of the endeavour to retain the regal power in legally undiminished fulness. They were thus led not to break up the royal office into parts or to transfer it from an individual to a college, but simply to double it and thereby, if necessary, to neutralize it through its own action.

As regards the termination of their tenure of office, the earlier -interregnum- of five days furnished a legal precedent. The ordinary presidents of the community were bound not to remain in office longer than a year reckoned from the day of their entering on their functions[4]; and they ceased de jure to be magistrates upon the expiry of the year, just as the interrex on the expiry of the five days. Through this set termination of the supreme office the practical irresponsibility of the king was lost in the case of the consul. It is true that the king was always in the Roman commonwealth subject, and not superior, to the law; but, as according to the Roman view the supreme judge could not be prosecuted at his own bar, the king might doubtless have committed a crime, but there was for him no tribunal and no punishment. The consul, again, if he had committed murder or treason, was protected by his office, but only so long as it lasted; on his retirement he was liable to the ordinary penal jurisdiction like any other burgess.

To these leading changes, affecting the principles of the constitution, other restrictions were added of a subordinate and more external character, some of which nevertheless produced a deep effect. The privilege of the king to have his fields tilled by task-work of the burgesses, and the special relation of clientship in which the metoeci as a body must have stood to the king, ceased of themselves with the life tenure of the office.

Hitherto in criminal processes as well as in fines and corporal punishments it had been the province of the king not only to investigate and decide the cause, but also to decide whether the person found guilty should or should not be allowed to appeal for pardon. The Valerian law now (in 245) enacted that the consul must allow the appeal of the condemned, where sentence of capital or corporal punishment had been pronounced otherwise than by martial law - a regulation which by a later law (of uncertain date, but passed before 303) was extended to heavy fines. In token of this right of appeal, when the consul appeared in the capacity of judge and not of general, the consular lictors laid aside the axes which they had previously carried by virtue of the penal jurisdiction belonging to their master. The law however threatened the magistrate, who did not allow due course to the provocatio, with no other penalty than infamy--which, as matters then stood, was essentially nothing but a moral stain, and at the utmost only had the effect of disqualifying the infamous person from giving testimony. Here too the course followed was based on the same view, that it was in law impossible to diminish the old regal powers, and that the checks imposed upon the holder of the supreme authority in consequence of the revolution had, strictly viewed, only a practical and moral value. When therefore the consul acted within the old regal jurisdiction, he might in so acting perpetrate an injustice, but he committed no crime and consequently was not amenable for what he did to the penal judge.