Common law
The common lawso named because it was "common" to all the king's courts across Englandoriginated in the practices of the courts of the English kings in the centuries following the Norman Conquest in 1066. Prior to the Norman Conquest, much of England's legal business took place in the local folk courts of its various shires and hundreds. A variety of other individual courts also existed across the land: urban boroughs and merchant fairs held their own courts, as did the universities of Oxford and Cambridge, and large landholders also held their own manorial and seigniorial courts as needed. Additionally, the Catholic Church operated its own court system that adjudicated issues of canon law.
Legal origins theory
While English common law originated in thirteenth century England and has then been transplanted through colonization and occupation to England’s ex-colonies (United States, Canada, Australia, and several countries in Central America, Africa and Asia), the Scandinavian common law was developed in Denmark and Sweden and the German common law sprang in Germany and Switzerland [Guerriero 2016a, p. 54]. These last four countries then exported their common law model to the respective colonies or to those jurisdictions (China, Greece, Japan, Romania, South Korea, Taiwan, Thailand, and Turkey), which were never colonized but borrowed their initial legal order from the European codes considered most advanced at the time [Guerriero 2016a, p. 54]. Civil law instead has its roots in Roman law, was incorporated by the Napoleonic codes first and then by both the Austrian and Russian Civil codes, and has been then introduced via mainly colonization and occupation into continental Europe, the Near East, Latin America, Africa, and Indochina. Bulgaria, Ethiopia, Iran, and Kazakhstan instead purposely borrowed their initial legal order from either France, Russia, or England [Guerriero 2016a, p. 54].