Secret police organizations originated in 18th-century Europe after the French Revolution and the Congress of Vienna. Such operations were established in an effort to detect any possible conspiracies or revolutionary subversion. The peak of secret-police operations in most of Europe was 1815 to 1860, "when restrictions on voting, assembly, association, unions and the press were so severe in most European countries that opposition groups were forced into conspiratorial activities."Robert Justin Goldstein, Political Repression in 19th Century Europe (1983; Routledge 2013 ed.) The Geheime Staatspolizei of Austria and the Geheimpolizei of Prussia were particularly notorious during this period. After 1860, the use of secret police declined due to increasing liberalization, except in autocratic regimes such as Tsarist Russia.
