It is the Roman legal system which has had an influence on Western Europe. The Romans developed their own legal system without Greek influence. Greek influence on the Romans was mainly in the fields of philosophy and art. Roman civil law has had an influence on European civil law through the Corpus Juris Civilis (Body of Civil Law) which was dubbed Justinian Code in the 16th century. It was commissioned by the emperor Justinian I in the sixth century. It was a review of imperial laws going back 400 years (to the time of Hadrian). It scrapped obsolete or unnecessary laws, made changes when necessary and clarified obscure passages. Its aim was to put the laws into books (previously they were written on many different scrolls), harmonise conflicting views among jurists which arose from centuries of poorly organised development of Roman law and have a uniform and coherent body of law. It also included the Institutiones (a textbook for first year law students), the Digesta (a collection of fragments taken from essays on laws written by jurists, which was used as an advanced law student textbook) and the Novellae Constitutiones (a collection of the laws issued by Justinian). This collection of books was rediscovered in a library in Pisa in 1070. It had a big impact. Bologna University (established in 1088) was the first university in Europe and its major appeal was its faculty of law, which had four professors who specialised in studying interpreting this work. It attracted student all over Europe. The Corpus Juris Civilis became the plank of the development an emerging class of professional lawyers. It became the foundation of the law in the Italian city-states of the high Middle Ages and the Renaissance. The Holy Roman Emperor Frederick I (reigned 1155--1190) was the first dynastic ruler to hire professional lawyers to run his administration, which became based on the "Justinian Code". The use of Roman law provided a new rationale for imperial rule as the emperors' traditional claim to divine right to rule had been challenged. Since Roman law was based on natural moral law and the principle of rationality, it provided a system of law of for the imperial state which was a reflection these principles and which was separate from religion. It also provided a framework which ensured consistency in administration. The Corpus Juris Civilis was also used to formulate the Napoleonic Code in 1804. This replaced the existing uncoordinated and contradictory web of separate old feudal and royal French laws. This code was different than the Justinian Code, which was a collection of edited or revised extracts of law. It was more systematic. Nevertheless, the latter provided material which was important in the creation this code, which was Europe's first modern code of civil law. Following the French example, many continental European countries later also compiled their codes of civil law and they, too, used the Corpus Juris Civilis as its foundation.
