An important common characteristic of civil law, aside from its origins in Roman law, is the comprehensive codification of received Roman law, i.e., its inclusion in civil codes. The earliest codification known is the Code of Hammurabi, written in ancient Babylon during the 18th century BC. However, this, and many of the codes that followed, was mainly lists of civil and criminal wrongs and their punishments. The codification typical of modern civilian systems did not first appear until the Justinian Code.
Germanic codes appeared over the 6th and 7th centuries to clearly delineate the law in force for Germanic privileged classes versus their Roman subjects and regulate those laws according to folk-right. Under feudal law, a number of private custumals were compiled, first under the Norman empire (Très ancien coutumier, 1200–1245), then elsewhere, to record the manorial – and later regional – customs, court decisions, and the legal principles underpinning them. Custumals were commissioned by lords who presided as lay judges over manorial courts in order to inform themselves about the court process. The use of custumals from influential towns soon became commonplace over large areas. In keeping with this, certain monarchs consolidated their kingdoms by attempting to compile custumals that would serve as the law of the land for their realms, as when Charles VII of France in 1454 commissioned an official custumal of Crown law. Two prominent examples include the Coutume de Paris (written 1510; revised 1580), which served as the basis for the Napoleonic Code, and the Sachsenspiegel (c. 1220) of the bishoprics of Magdeburg and Halberstadt which was used in northern Germany, Poland, and the Low Countries.
The concept of codification was further developed during the 17th and 18th centuries AD, as an expression of both natural law and the ideas of the Enlightenment. The political ideals of that era were expressed by the concepts of democracy, protection of property and the rule of law. Those ideals required certainty of law, recorded, uniform law. So, the mix of Roman law and customary and local law gave way to law codification.
Also, the notion of a nation-state implied recorded law that would be applicable to that state.
There was also a reaction to law codification. The proponents of codification regarded it as conducive to certainty, unity and systematic recording of the law; whereas its opponents claimed that codification would result in the ossification of the law.
In the end, despite whatever resistance to codification, the codification of European private laws moved forward. Codifications were completed by Denmark (1687), Sweden (1734), Prussia (1794), France (1804), and Austria (1811). The French codes were imported into areas conquered by Napoleon and later adopted with modifications in Poland (Duchy of Warsaw/Congress Poland; Kodeks cywilny 1806/1825), Louisiana (1807), Canton of Vaud (Switzerland; 1819), the Netherlands (1838), Serbia (1844), Italy and Romania (1865), Portugal (1867) and Spain (1888). Germany (1900), and Switzerland (1912) adopted their own codifications. These codifications were in turn imported into colonies at one time or another by most of these countries. The Swiss version was adopted in Brazil (1916) and Turkey (1926).
In the United States, U.S. states began codification with New York’s “Field Code” (1850), followed by California’s codes (1872), and the federal revised statutes (1874) and the current United States Code (1926).
In Japan, at the beginning of the Meiji Era, European legal systems—especially the civil law of Germany and France—were the primary models for the judicial and legal systems. In China, the German Civil Code was introduced in the later years of the Qing dynasty, emulating Japan. In addition, it formed the basis of the law of the Republic of China, which remains in force in Taiwan. Furthermore, Korea, Taiwan, and Manchuria, former Japanese colonies have been strongly influenced by the Japanese legal system.
Some authors consider civil law the foundation for socialist law used in communist countries, which in this view would basically be civil law with the addition of Marxist-Leninist ideals. Even if this is so, civil law was generally the legal system in place before the rise of socialist law, and some Eastern European countries reverted to the pre-socialist civil law following the fall of socialism, while others continued using socialist legal systems.
Several civil-law mechanisms seem to have been borrowed from medieval Islamic Sharia and fiqh. For example, the Islamic hawala (hundi) underlies the avallo of Italian law and the aval of French and Spanish law.