Ever since populations began to concentrate in urban regions, policing became a major issue for urban societies. In periods of instability, important changes became established, such as more organized posts and informal agreements that formed organized protection in regions. Nevertheless, policing was not formally developed until the 17th century in Paris and
and early 19th century in Britain. It was the rapid growth of Paris and London that forced the creation of formal and dedicated police officers. In the 18th century, policing began to diverge into formal and professional roles for investigations as well as protection of citizens.