Fausset's Bible Dictionary
Roman emperor, reigning at Christ's birth (Luk_2:1,
etc.). His decree that all the world should be taxed, each going to his
own city, was the divinely ordered (Mic_5:2)
occasion of Jesus' birth taking place at Bethlehem. Born 63 B.C. Also
called Octavius and Octavianus from his father, who died while he was
young. Educated by his great uncle Julius Caesar, triumvir with Antony
and Lepidus. Dissension having arisen, Octavianus overcame Antony, and
gained supreme power at the battle of Actium, 31 B.C.
Saluted emperor (imperator, military commander in chief originally), and surnamed Augustus Caesar, "majestic." Leaving the names and rights of the chief republican officers unchanged, he united them all, one by one, in himself. Herod, who had been on Antony's side, he not only pardoned, but even increased in power; Herod thereby became attached to his dynasty, and built him a temple of marble near the sources of the Jordan. Augustus Caesar died at Nola in Campania, in his 76th year, A.D. 14. Some time before his death he associated Tiberius with himself in the empire (Luk_3:1).
Taken from: Fausset's Bible Dictionary by Andrew Robert Fausset (1821-1910)