Luke 2:1-5
Now it happened at this time Caesar Augustus issued a decree that a census should be made of the whole inhabited world...and everyone went to be registered, each to his own town. So Joseph set out from the town of Nazareth in Galilee, to David's town called Bethlehem, since he was of David's house and line, in order to be registered together with Mary, his betrothed, who was with child.