About that time Caesar Augustus ordered a census to be taken throughout the Empire. This was the first census when Quirinius was governor of Syria. Everyone had to travel to his own ancestral hometown to be accounted for. So Joseph went from the Galilean town of Nazareth up to Bethlehem in Judah, David’s town, for the census. As a descendant of David, he had to go there. He went with Mary, his fiancée, who was pregnant.
The Roman Centurion
This is one of Caesar Augustus' guys. He was asked to let people know about the census. Everyone needed to travel back to their hometowns in order to be counted up... official government stuff! But really, without the census, Mary & Joseph wouldn't have gone to Bethlehem, which was the place where Jesus was supposed to be born! It's a good job he did...