In the two definite survivals of the Roman monarchy election was not recognised; the dictator was nominated by the consul, not by his predecessor, for it was only an occasional office; and the rex sacrorum was nominated by the pontifex maximus,[1] no longer by the preceding rex; for this office simply continued the priestly functions of the king, the religious headship being vested in the pontifex. This oldest principle of appointment survived in Republican Rome as an integral part of the elective process, to reappear again in the Principate, in cases where election had become a mere form, as the living principle.[2] It is, in fact, the one principle that has a continuous history; election is the Republican interlude.
If, therefore, we are led to consider the monarchy as not purely an elective office, and substitute for election the principle of nomination, we must consider that it was the right, and probably the duty, of the king of Rome to nominate his successor. If there had been no due nomination during his lifetime, and consequently no distinctly marked out successor to the monarchy, the duty of providing such a successor lapsed to the Senate, from which body the interrex was appointed. The interregnum is said by tradition to have dated from the first vacancy in the regal office, after the death of Romulus.[3] When such a vacancy had occurred, the auspices, under which the state had been founded, and which were the mark of divine acceptance of the kingly rule, "returned to the patres,"[4] and we are told that this was from the first interpreted to mean, not to the comitia curiata, but to the patrician Senate. The earliest interregnum is represented as an exercise of collective rule by the Senate; but, on the analogy of the sole magistracy, it took the form of a creation of a succession of interreges. The first step was the division of the Senate into decuriae;[5] each decury had fifty days of government allotted to it; within this period each individual member of the decuria exercised rule for five days, and, according to one account, the succession of the decuries was determined by lot (sortitio).[6] The rule is represented as collegiate, the whole decury possessing the imperium, whilead Brut. i. 5, 4.].]
