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.
Law in Europe
The law of Europe has a diverse history. Roman law underwent major codification in the Corpus Juris Civilis of Emperor Justinian, as later developed through the Middle Ages by medieval legal scholars. In Medieval England, judges retained greater power than their continental counterparts and began to develop a body of precedent. Originally civil law was one common legal system in much of Europe, but with the rise of nationalism in the 17th century Nordic countries and around the time of the French Revolution, it became fractured into separate national systems. This change was brought about by the development of separate national codes, of which the French Napoleonic Code and the German and Swiss codes were the most influential. Around this time civil law incorporated many ideas associated with the Enlightenment. The European Union's Law is based on a codified set of laws, laid down in the Treaties. Law in the EU is however mixed with precedent in case law of the European Court of Justice. In accordance with its history, the interpretation of European law relies less on policy considerations than U.S. law.