Where did common law originate?
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.
Civil law (legal system)
Louisiana private law is primarily a Napoleonic system. Louisiana is the only U.S. state partially based on French and Spanish codes and ultimately Roman law, as opposed to English common law. In Louisiana, private law was codified into the Louisiana Civil Code. Current Louisiana law has converged considerably with American law, especially in its public law, judicial system, and adoption of the Uniform Commercial Code (except for Article 2) and certain legal devices of American common law. In fact, any innovation, whether private or public, has been decidedly common law in origin. Quebec law, whose private law is also of French civil origin, has developed along the same lines, adapting in the same way as Louisiana to the public law and judicial system of Canadian common law. By contrast, Quebec private law has innovated mainly from civil sources. To a lesser extent, other states formerly part of the Spanish Empire, such as Texas and California, have also retained aspects of Spanish civil law into their legal system, for example community property. The legal system of Puerto Rico exhibits similarities to that of Louisiana: a civil code whose interpretations rely on both the civil and common law systems. Because Puerto Rico's Civil Code is based on the Spanish Civil Code of 1889, available jurisprudence has tended to rely on common law innovations due to the code's age and in many cases, obsolete nature.