Did you ancestors live under a King, a Czar, a Prince or Princess, or a local Count? Or were they aristocrats and rulers themselves? (Pay attention to the history of the region they came from and learn who was ruling their lives.) Many towns that were under occupation have changed names several times. For instance, some places in Central and Eastern Europe have names in German, Polish, Russian, and local languages. Likewise, the records you are seeking may be moved from one archive to another. In some European countries, records were kept by the Catholic church for many villages, because the priest may have been the only person who could read and write - and your ancestor need not have been a Catholic to be recorded.
In the United States large counties were split into smaller ones as populations increased. Don't get "county bound" and research paths of migration.
