Yale Law School

Canon law is only in use by members of the Catholic Church, the Eastern Orthodox Church and the Anglican Communion. Common law originated from England and has been inherited by almost every country once tied to the British Empire (except Malta, Scotland, the U.S. state of Louisiana, and the Canadian province of Quebec). In medieval England, the Norman conquest the law varied shire-to-shire, based on disparate tribal customs. The concept of a “common law” developed during the reign of Henry II during the late 12th century, when Henry appointed judges that had authority to create an institutionalised and unified system of law “common” to the country. The next major step in the evolution of the common law came when King John was forced by his barons to sign a document limiting his authority to pass laws.

Aaron Perzanowski, coauthor of The End of Ownership, researches intellectual and …