The study is devoted to the Bohemian and Moravian royal towns and their contribution to the protection of the peace and security of the country from the end of the thirteenth to the beginning of the fi fteenth century. The original legal jurisdiction of the towns was extended by monarchical privileges to include the punishment of public criminals and robbers who threatened the country, the inhabitants of the towns and their economic interests. Some towns formed alliances for mutual protection and assistance under the mandate of the monarch. Threatened towns could also take action against aristocratic castles in their vicinity, and new castles could only be built near towns with the consent of the monarch. The royal towns were also involved in legal measures against public criminals, which were introduced in Bohemia at the beginning of the fi fteenth century.