A member of the aristocratic family of the Symmachi, he was the son of Aurelius Valerius Tullianus Symmachus, consul for 330.
Avianius was among the senators who had not converted to Christianity and continued to practice the traditional state religion of Rome,[2] and was member of several priestly collegia, including the Pontefices Vestae and the quindecimviri sacris faciundi (from 351 to 375).
[8] According to the story told by Ammianus, the riot originated from a rumour, diffused by a member of the plebs, according to which Symmachus, during his prefecture, had said that "he would prefer putting out the limekilns with his own wine, to selling the lime at the price expected of him"; forgetting the prosperity achieved during Symmachus' office, the enraged plebs burnt down his house.
[15] The following year, his memory was honoured with a gilded statue, erected by imperial decree after a request of the Senate, on 29 April.
He composed a small number of epigrams of low quality about members of the Constantinian age, such as Amnius Anicius Iulianus and Lucius Aradius Valerius Proculus.