Since earliest times people have built walls to protect themselves and their belongings—walls around country estates controlled livestock and protected the animals from marauding wolves or poachers. With equal determination their enemies and rivals have tried to break through those walls to kill and steal. When a strong central authority protects borders and reduces internal crime, people have little need for fortified dwellings, although the rulers may build walls and towers to define legitimate residents and defend the country against external threats. When central authority breaks down, however, individuals are more likely to fortify their homes. The presence of castles in the landscape indicates a decline in stability and peace.