Information Age
The story of the location of Jesus’ birth might be said to begin when the Israelites first settled in Canaan. The tribe of Judah was given much of the southern lands, including the village of Bethlehem. Hundreds of years later, when the future King David was born, the tribe of Judah continued to possess Bethlehem. Centuries later, after the exiles of the Northern and Southern Kingdoms, the lines of tribal ownership seem to have dimmed in importance.
By the time of Jesus’ birth, it probably wasn’t unusual that Joseph, of the tribe of Judah, was located in Nazareth, far to the north of the original land of Judah. The Bible gives no reason why Joseph was located there, but Luke 2:4 says Joseph had to go from Nazareth in Galilee to Bethlehem in Judea because he had to register there for the new census. It says he had to go to Bethlehem because he was of the house and line of David.
The details for the census are lost, but it is highly likely it was taken for at least two reasons: taxation and counting men eligible for the military. Historians argue about when and if the Jews were exempt for service in the Roman military, but it is highly likely the Romans would have at least wanted to know how many might be available to fight for—or against—Rome.