Obnuntiatio: when the auspices halted the assemblies of Rome
The right to announce adverse signs, the Aelian and Fufian laws, Bibulus watching the sky in 59 BC: how the auspices became a weapon in Roman politics.
In republican Rome no popular assembly could meet, no law could be voted on and no magistrate could be elected unless the auspices had been taken. This link between religion and politics gave magistrates a powerful tool: the possibility of announcing unfavourable signs and thereby preventing an assembly from taking place. In Latin this announcement was called obnuntiatio.
Lightning and the assemblies
An ancient rule laid down that when Jupiter thundered or hurled lightning it was not lawful to hold assemblies of the people. Cicero mentions it in De divinatione, ironically noting that lightning on the left, considered favourable in many other circumstances, became unfavourable precisely for assemblies. It was therefore enough for a magistrate to declare that he had seen a flash for the meeting to be postponed.
The augurs had a similar power. In De legibus Cicero recalls that an augur could dissolve an assembly by pronouncing the formula alio die, “on another day”. A single word was enough to interrupt political business, and for this reason the college enjoyed an influence that went far beyond the religious sphere, so much so that many politicians were eager to become members.
The Aelian and Fufian laws
Around the middle of the second century BC two laws, the lex Aelia and the lex Fufia, regulated the use of the auspices in assemblies. Their precise content is debated by scholars, but they seem to have recognised the right of magistrates to block meetings by announcing unfavourable signs. Cicero regarded them as a bulwark of public tranquillity against the initiatives of the most daring tribunes.
Bibulus and the watched sky
The most famous case dates from 59 BC. The consul Marcus Calpurnius Bibulus, an opponent of his colleague Caesar, after being driven violently from the Forum, withdrew to his house and for the rest of the year had it announced by edicts that he was watching the sky. According to the doctrine, this was enough to make illegitimate any assembly called on the days of his observation. Caesar ignored the announcements and had his laws passed.
The validity of those laws remained disputed for years, and Caesar's opponents used it as a political argument. The following year the tribune Publius Clodius had a law passed restricting the use of obnuntiatio, although its exact scope remains uncertain. The religion of the auspices had become a weapon in the crisis of the Republic, and each side interpreted it to its own advantage.
Contemporaries themselves were aware of this instrumental use. Cicero, while defending the Aelian and Fufian laws, admitted in De divinatione that many augural rules were preserved above all for their political usefulness. Obnuntiatio thus displayed with particular clarity the double face of Roman public religion, poised between reverence for the gods and the calculation of power.
This affair clearly reveals the nature of Roman augury. It was not a system for knowing the future but a set of rules defining when a public action was legitimate. For this very reason it could be used and abused. With the coming of the Empire, when the assemblies lost their importance, obnuntiatio also lost most of its political significance.