The occasions of the magistrate’s auspication embraced every public act of any importance. In three cases above all was it regarded as essential; these were the nomination of a magistrate, the holding of the _comitia_, and the departure of a general for war. The chief rule of observance was that the auspices must be taken on the same day and in the same place in which the act was to be performed. The fact that the Roman civil day (_dies civilis_) began at midnight[691] was convenient for procuring the requisite _silentium_; and sometimes, to prevent any flaw (_vitium_), the act itself was performed before daybreak. Thus the consul, when he nominates a dictator, “rises in the stillness of the night”[692] to do so. The ceremonial for all public auspication[693] was as follows. A sacred enclosure (_templum_) was marked out on the required spot—within or without the _pomerium_, according to the purpose in view—within which the magistrate pitched his tent (_tabernaculum capere_),[694] which had one side open for observation. After midnight he rose, and, seated on the floor, performed the rite. Its validity depended on his personal observation alone; but he might invite skilled assistants to his aid.[695] The consequence of inability to get a favourable omen was necessarily the non-performance of the contemplated act; the only course open was to wait for another day, and to seek the auspices over again (_repetere auspicia_).[696] If the act had been performed in spite of ill omens, or if subsequent reflection showed a flaw in the ceremonial, the act was said to be subject to a _vitium_ which rendered it invalid; the law passed did not hold good, and the magistrate thus faultily elected (_vitio creatus_) had to resign his functions.[697] In the case of the election of the consuls being thus vitiated the consequences might be serious; for if the flaw was discovered after their entrance on office, a renewal of the auspices (_renovatio auspiciorum_)[698] could only be effected through an _interregnum_. It was in this connexion that the power of the augurs came into play, for they were the interpreters of the heaven-sent signs. It was no wonder that membership of the augural college was the highest ambition of the Roman statesman, when its decree could upset a law, stave off a capital charge, or force a consul to abdicate. It is true that the augurs could give their advice only on the request of a magistrate or of the Senate; but, as a measure or election not favoured by the government would readily be challenged in this way, the decision as to the future of the state often rested wholly with the college of augurs. Their power of interpretation extended to the far more frequent _auspicia oblativa_, and in reporting these even the initiative might, as we shall see, be taken by an augur.