Admiralty law
The common law courts originally took a very limited view of their own jurisdiction. They considered themselves to lack jurisdiction over a defendant until he had voluntarily submitted to it by entering a plea seeking judgment from the court. Obviously, a criminal justice system that could punish only those who had volunteered for possible punishment was unworkable; a means was needed to coerce them into entering a plea. Alternatively, individuals were frequently tried under Admiralty law, as observed by Henry de Bracton.