Saudi Arabia recognises Quran as its constitution, and is governed on the basis of Islamic law. Iran has also witnessed a reiteration of Islamic law into its legal system after 1979. During the last few decades, one of the fundamental features of the movement of Islamic resurgence has been the call to restore the Sharia, which has generated a vast amount of literature and affected world politics. The Catholic Church has the oldest continuously functioning legal system in the western world, predating the evolution of modern European civil law and common law systems. The Eastern Catholic Churches, which developed different disciplines and practices, are governed by the Code of Canons of the Eastern Churches. The canon law of the Catholic Church influenced the common law during the medieval period through its preservation of Roman law doctrine such as the presumption of innocence.
- Energy, gas, telecomms and water are regulated industries