Luke 2:1, 3-7

Now it came to pass in those days, there went out a decree from Cæsar Augustus, that all the world should be enrolled.

And all went to enrol themselves, every one to his own city. And Joseph also went up from Galilee, out of the city of Nazareth, into Judæa, to the city of David, which is called Bethlehem, because he was of the house and family of David; to enrol himself with Mary, who was betrothed to him, being great with child. And it came to pass, while they were there, the days were fulfilled that she should be delivered. And she brought forth her firstborn son; and she wrapped him in swaddling clothes, and laid him in a manger, because there was no room for them in the inn.