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
Judge-made common law operated as the primary source of law for several hundred years, before Parliament acquired legislative powers to create statutory law. It is important to understand that common law is the older and more traditional source of law, and legislative power is simply a layer applied on top of the older common law foundation. Since the 12th century, courts have had parallel and co-equal authority to make law—"legislating from the bench" is a traditional and essential function of courts, which was carried over into the U.S. system as an essential component of the "judicial power" specified by Article III of the U.S. Constitution. Justice Oliver Wendell Holmes, Jr. summarized centuries of history in 1917, "judges do and must legislate." There are legitimate debates on how the powers of courts and legislatures should be balanced. However, the view that courts lack law-making power is historically inaccurate and constitutionally unsupportable.