There was no full Roman empire census. The Roman’s liked a census, but they used them to know who is where (and paying taxes), not who’s ancestors have come from where. The Roman Empire would have been chaotic if everybody in it had to travel back to their ancestral home (huge distances, huge numbers, people who’s ancestral home is no longer part of the empire, people who are no longer in the empire, but their ancestral home is). The census as described by “Luke” does not match historical documents, so maybe the 4th century bishops who chose the gospels made a mistake including it?
