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.
Common law
Examples of common law being replaced by statute or codified rule in the United States include criminal law (since 1812, U.S. federal courts and most but not all of the States have held that criminal law must be embodied in statute if the public is to have fair notice), commercial law (the Uniform Commercial Code in the early 1960s) and procedure (the Federal Rules of Civil Procedure in the 1930s and the Federal Rules of Evidence in the 1970s). But note that in each case, the statute sets the general principles, but the interstitial common law process determines the scope and application of the statute.