The primitive Senate is credited with two standing powers—the _patrum auctoritas_ and the initiation of an _interregnum_. Neither of these prerogatives was directly contemplated by the constitution, and the Senate never becomes a corporation possessing powers in its own right until the time of the Empire. Tradition mentions the “authority of the fathers” as being necessary for the appointment of a new king; it leaves it to be inferred that it was required for the validity of laws as well, an inference probably not true of the period of the monarchy. As we have already explained, it was a legal right only in so far as it was an extreme instance of the necessity the magistrate was under of taking advice. Perhaps towards the close of the monarchy, with reference to the choice of a successor to the throne, custom had made it a standing prerogative. The _interregnum_ rests on a somewhat different basis; it was a power which religion enjoined should be in the hands of the whole patrician community—usage had delegated the power to the patrician Senate; so here again we have a prerogative which rested wholly on custom. A privilege only less constant than these was probably the control of foreign policy. The formula of the Fetiales, which is said to have dated from their institution during the monarchy, contains the clause: “But on these matters we will consult the elders at home, how we may obtain our rights.”[241] It was thus the duty of the king to consult the Senate in all matters affecting the international relations of the state. For a declaration of war, perhaps, even this was not sufficient. Tradition believed that, in this matter, reference must be made to the people assembled in the _comitia curiata_.[242] On the other hand, the right of making treaties (_foedera_) with states could not have been limited in this way. For the treaty made in time of peace the Senate, and perhaps the people, were consulted; but this could hardly have been the case with the treaty which closed a war and which was made on the field of battle. In the Republic there survives a shadowy and disputed right of the _imperator_ in the field to make a treaty which shall bind the people. The right was denied, but only on the ground that the general could not take an oath binding on the public conscience. But the king was at once general and high-priest; he could doubtless take this oath even without the assistance of his servants, the Fetiales.