English law
Common law is a term with historical origins in the legal system of England. It denotes, in the first place, the judge-made law that developed from the early Middle Ages as described in a work published at the end of the 19th century, "The History of English Law before the Time of Edward I", in which Pollock and Maitland expanded the work of Coke (17th century) and Blackstone (18th century). Specifically, the law developed in England's Court of Common Pleas and other common law courts, which became also the law of the colonies settled initially under the crown of England or, later, of the United Kingdom, in North America and elsewhere; and this law as further developed after those courts in England were reorganised by the Supreme Court of Judicature Acts passed in the 1870s, and developed independently, in the legal systems of the United States and other jurisdictions, after their independence from the United Kingdom, before and after the 1870s. The term is used, in the second place, to denote the law developed by those courts, in the same periods (pre-colonial, colonial and post-colonial), as distinct from within the jurisdiction, or former jurisdiction, of other courts in England: the Court of Chancery, the ecclesiastical courts, and the Admiralty court.
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].