Census
From Conservapedia
A census is a counting of all individuals within a given area where more specific demographic information is usually collected as well. The United States government takes a census every 10 years.
Biblical Refences
Jesus was born during a Roman census dictated by Augustus Caesar. Because of this census and the decree that all inhabitants were to register based on their tribal House, Joseph had to go back to Bethlehem. If the census had never occurred, then Jesus would not have been born in Bethlehem.
