Anglo-American Law In England after the Norman Conquest the feudal law was ultimately replaced by the law of the royal courts, such as the king's bench. The royal courts developed common law, i.e., judicial legislation as opposed to the law of the formally enacted statute. Common law adhered excessively to precedent, and equity, exercised by the king's chancery, appeared, with its reliance upon the dictates of conscience rather than upon precedent. The two systems became bitter rivals. In the early 17th cent. Francis Bacon championed equity, while such eminent jurists as Edward Coke upheld the common law. In the 18th cent. English jurisprudence stressed natural law (the theory that law must incorporate the natural rights of humans), and the highly influential work of Sir William Blackstone exemplifies the theory. The work of Blackstone was the most important influence in U.S. law (except for Louisiana, Puerto Rico, and the Virgin Islands, where Continental civil law prevailed). Among those who helped to develop the American concept of law were James Kent and Joseph Story; in constitutional law the most important figure was John Marshall. In the United States the distinctive feature is the coexistence of federal and state law, for the U.S. Constitution limits the sphere in which federal law is supreme.