E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Libra, the 7th sign of the zodiac, which contains the autumnal equinox. According to fable it is Astræa, who, in the iron age, returned from earth to heaven. Virgil, to praise the equity of Augustus, promises him a future residence in this sign.
According to Persian mythology, at the last day there will be a huge balance big as the vault of heaven. The two scale pans will be called that of light and that of darkness. In the former all good will be placed, in the latter all evil. And each individual will receive an award according to the judgment of the balance.