It was during his stay in Asia (20 B.C.) that the Parthian king Phraates voluntarily restored the Roman prisoners and standards taken at Carrhae (53 B.C.), a welcome tribute to the respect inspired by Augustus, and a happy augury for the future.
He wrote a work on augury, the first book of which he dedicated to Cicero.
Troops in this victory were a good augury for the future.
The latter is said to have appealed to augury to determine the exact site of his projected foundation; but less fantastic considerations went far to settle it.
The science of augury was contained in various written works, which were consulted as occasion arose: such were the libri augurum, a manual of augural ritual, and the commentarii augurum, a collection of decrees or answers given by the college to the senate in certain definite cases.
It is now generally agreed that the science of augury is of Italian, not Etruscan, origin.
On the other hand, as the result in part of the theory of Stoicism, religion passed into the hands of the politicians: cults were encouraged or suppressed from political motives, the membership of the colleges of pontifices and augurs, now conferred by popular vote, was sought for its social and political advantages, and augury was debased till it became the meanest tool of the politician.