The cognomen of the first Roman emperor, C. Julius Caesar Octavianus, during whose reign Christ was born (Luke 2:1). His decree that “all the world should be taxed” was the divinely ordered occasion of Jesus’ being born, according to prophecy (Micah 5:2), in Bethlehem. This name being simply a title meaning “majesty” or “venerable,” first given to him by the senate (B.C. 27), was borne by succeeding emperors. Before his death (A.D. 14) he associated Tiberius with him in the empire (Luke 3:1), by whom he was succeeded.
Augustus
Caesar Augustus never speaks in the New Testament, yet his name frames some of its best-known moments. Luke 2:1 opens the Christmas story with his decree that “all the world should be taxed.” Later, in Acts, Paul appeals to Augustus, which is why a centurion named Julius, of “Augustus’ band,” is given charge of him for the sea voyage to Italy. The title stands for the Roman emperor, the distant ruler whose orders move ordinary people, from a village couple to a prisoner, across the map.
4 verses
Luke
And it came to pass in those days, that there went out a decree from Caesar Augustus, that all the world should be taxed.
Acts
But when Paul had appealed to be reserved unto the hearing of Augustus, I commanded him to be kept till I might send him to Caesar.
But when I found that he had committed nothing worthy of death, and that he himself hath appealed to Augustus, I have determined to send him.
And when it was determined that we should sail into Italy, they delivered Paul and certain other prisoners unto one named Julius, a centurion of Augustus' band.
From Easton's Bible Dictionary
Matthew George Easton, 1897