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. The British Empire spread the English legal system to its historical colonies, many of which retain the common law system today. These "common law systems" are legal systems that give great precedential weight to common law, and to the style of reasoning inherited from the English legal system.
Middle Ages
Legal studies advanced during the 12th century. Both secular law and canon law, or ecclesiastical law, were studied in the High Middle Ages. Secular law, or Roman law, was advanced greatly by the discovery of the "Corpus Juris Civilis" in the 11th century, and by 1100 Roman law was being taught at Bologna. This led to the recording and standardisation of legal codes throughout Western Europe. Canon law was also studied, and around 1140 a monk named Gratian (fl. 12th century), a teacher at Bologna, wrote what became the standard text of canon law—the "Decretum".