“In those days,

A decree went out

From the Emperor

Caesar Augustus

That all the world

Should be registered.”

Ἐγένετο δὲ ἐν ταῖς ἡμέραις ἐκείναις ἐξῆλθεν δόγμα παρὰ Καίσαρος Αὐγούστου ἀπογράφεσθαι πᾶσαν τὴν οἰκουμένην.

Luke tried to put these events within a historical perspective.  He said that in those days (Ἐγένετο δὲ ἐν ταῖς ἡμέραις), a decree or dogma went out (ἐξῆλθεν δόγμα) from the Emperor, Caesar Augustus (παρὰ Καίσαρος Αὐγούστου), that all the world should be registered (ἀπογράφεσθαι πᾶσαν τὴν οἰκουμένην).  Could all the world be registered in a census?  Luke referred to the Roman Emperor, Caesar Augustus, who ruled the Roman empire with his famous Pax Romana, or peace everywhere, from 27 BCE to 14 CE, precisely the time of these events.  Augustus was born in 63 BCE so that he would have been 77 years old when he died.  He was sometimes called god, son of god, savior, or father.  As the adopted son of Julius Caesar, he defeated Mark Anthony and Cleopatra to gain sole control of the empire.  He set up an intricate set of taxes for the empire, so that there was a consent source of income.  Thus, the local tax collectors or publicans became rich, but disliked, official people in the empire.  The month of August was named after him, just as July was named after Julius Caesar.  However, there is no evidence of any call to register the whole world.  However, this would not have been inconsistent with his taxing plans, since the main reason for any registration or census would be for tax purposes.  Thus, this is possible, but unlikely.