The Common Law and Civil Law Traditions


court scene (Souvigny, woodcut)

Woodcut of a court scene from Praxis criminis persequendi, Jean Milles de Souvigny, 1541. The Robbins Collection.


Most nations today follow one of two major legal traditions: common law or civil law. The common law tradition emerged in England during the Middle Ages and was applied within British colonies across continents. The civil law tradition developed in continental Europe at the same time and was applied in the colonies of European imperial powers such as Spain and Portugal. Civil law was also adopted in the nineteenth and twentieth centuries by countries formerly possessing distinctive legal traditions, such as Russia and Japan, that sought to reform their legal systems in order to gain economic and political power comparable to that of Western European nation-states.

To an American familiar with the terminology and process of our legal system, which is based on English common law, civil law systems can be unfamiliar and confusing. Even though England had many profound cultural ties to the rest of Europe in the Middle Ages, its legal tradition developed differently from that of the continent for a number of historical reasons, and one of the most fundamental ways in which they diverged was in the establishment of judicial decisions as the basis of common law and legislative decisions as the basis of civil law. Before looking at the history, let’s examine briefly what this means.

Common law is generally uncodified. This means that there is no comprehensive compilation of legal rules and statutes. While common law does rely on some scattered statutes, which are legislative decisions, it is largely based on precedent, meaning the judicial decisions that have already been made in similar cases. These precedents are maintained over time through the records of the courts as well as historically documented in collections of case law known as yearbooks and reports. The precedents to be applied in the decision of each new case are determined by the presiding judge. As a result, judges have an enormous role in shaping American and British law. Common law functions as an adversarial system, a contest between two opposing parties before a judge who moderates. A jury of ordinary people without legal training decides on the facts of the case. The judge then determines the appropriate sentence based on the jury’s verdict.

Civil Law, in contrast, is codified. Countries with civil law systems have comprehensive, continuously updated legal codes that specify all matters capable of being brought before a court, the applicable procedure, and the appropriate punishment for each offense. Such codes distinguish between different categories of law: substantive law establishes which acts are subject to criminal or civil prosecution, procedural law establishes how to determine whether a particular action constitutes a criminal act, and penal law establishes the appropriate penalty. In a civil law system, the judge’s role is to establish the facts of the case and to apply the provisions of the applicable code. Though the judge often brings the formal charges, investigates the matter, and decides on the case, he or she works within a framework established by a comprehensive, codified set of laws. The judge’s decision is consequently less crucial in shaping civil law than the decisions of legislators and legal scholars who draft and interpret the codes.

The following sections explore the historical roots of these differences.

Historical Development of Civil Law

Mosaic of Emperor Justinian I

Mosaic of Emperor Justinian I, 6th CE. Basilica of San Vitale, Ravenna, Italy.


The term civil law derives from the Latin ius civile, the law applicable to all Roman cives or citizens. Its origins and model are to be found in the monumental compilation of Roman law commissioned by the Emperor Justinian in the sixth century CE. While this compilation was lost to the West within decades of its creation, it was rediscovered and made the basis for legal instruction in eleventh-century Italy and in the sixteenth century came to be known as Corpus iuris civilis. Succeeding generations of legal scholars throughout Europe adapted the principles of ancient Roman law in the Corpus iuris civilis to contemporary needs. Medieval scholars of Catholic church law, or canon law, were also influenced by Roman law scholarship as they compiled existing religious legal sources into their own comprehensive system of law and governance for the Church, an institution central to medieval culture, politics, and higher learning. By the late Middle Ages, these two laws, civil and canon, were taught at most universities and formed the basis of a shared body of legal thought common to most of Europe. The birth and evolution of the medieval civil law tradition based on Roman law was thus integral to European legal development. It offered a store of legal principles and rules invested with the authority of ancient Rome and centuries of distinguished jurists, and it held out the possibility of a comprehensive legal code providing substantive and procedural law for all situations.

As civil law came into practice throughout Europe, the role of local custom as a source of law became increasingly important—particularly as growing European states sought to unify and organize their individual legal systems. Throughout the early modern period, this desire generated scholarly attempts to systematize scattered, disparate legal provisions and local customary laws and bring them into harmony with rational principles of civil law and natural law. Emblematic of these attempts is the Dutch jurist Hugo Grotius’ 1631 work, Introduction to Dutch Jurisprudence, which synthesized Roman law and Dutch customary law into a cohesive whole. In the eighteenth century, the reforming aspirations of Enlightenment rulers aligned with jurists’ desire to rationalize the law to produce comprehensive, systematic legal codes including Austria’s 1786 Code of Joseph II and Complete Civil Code of 1811, Prussia’s Complete Territorial Code of 1794, and France’s Civil Code (known as the Napoleonic Code) of 1804. Such codes, shaped by the Roman law tradition, are the models of today’s civil law systems.

Historical development of English Common Law

Magna Carta, 1297 exemplar

Originally issued in the year 1215, the Magna Carta was first confirmed into law in 1225. This 1297 exemplar, some clauses of which are still statutes in England today, was issued by Edward I. National Archives, Washington, DC.


English common law emerged from the changing and centralizing powers of the king during the Middle Ages. After the Norman Conquest in 1066, medieval kings began to consolidate power and establish new institutions of royal authority and justice. New forms of legal action established by the crown functioned through a system of writs, or royal orders, each of which provided a specific remedy for a specific wrong. The system of writs became so highly formalized that the laws the courts could apply based on this system often were too rigid to adequately achieve justice. In these cases, a further appeal to justice would have to be made directly to the king. This difficulty gave birth to a new kind of court, the court of equity, also known as the court of Chancery because it was the court of the king’s chancellor. Courts of equity were authorized to apply principles of equity based on many sources (such as Roman law and natural law) rather than to apply only the common law, to achieve a just outcome.

Courts of law and courts of equity thus functioned separately until the writs system was abolished in the mid-nineteenth century. Even today, however, some U.S. states maintain separate courts of equity. Likewise, certain kinds of writs, such as warrants and subpoenas, still exist in the modern practice of common law. An example is the writ of habeas corpus, which protects the individual from unlawful detention. Originally an order from the king obtained by a prisoner or on his behalf, a writ of habeas corpus summoned the prisoner to court to determine whether he was being detained under lawful authority. Habeas corpus developed during the same period that produced the 1215 Magna Carta, or Great Charter, which declared certain individual liberties, one of the most famous being that a freeman could not be imprisoned or punished without the judgment of his peers under the law of the land—thus establishing the right to a jury trial.

In the Middle Ages, common law in England coexisted, as civil law did in other countries, with other systems of law. Church courts applied canon law, urban and rural courts applied local customary law, Chancery and maritime courts applied Roman law. Only in the seventeenth century did common law triumph over the other laws, when Parliament established a permanent check on the power of the English king and claimed the right to define the common law and declare other laws subsidiary to it. This evolution of a national legal culture in England was contemporaneous with the development of national legal systems in civil law countries during the early modern period. But where legal humanists and Enlightenment scholars on the continent looked to shared civil law tradition as well as national legislation and custom, English jurists of this era took great pride in the uniqueness of English legal customs and institutions.

That pride, perhaps mixed with envy inspired by the contemporary European movement toward codification, resulted in the first systematic, analytic treatise on English common law: William Blackstone’s (1723-1780) Commentaries on the Laws of England. In American law, Blackstone’s work now functions as the definitive source for common law precedents prior to the existence of the United States.

Civil law influences in American law

Sir William Blackstone by Thomas Gainsborough

Sir William Blackstone, 1774, by Thomas Gainsborough. Oil on canvas. Tate Collection, London.


The American legal system remains firmly within the common law tradition brought to the North American colonies from England. Yet traces of the civil law tradition and its importance in the hemisphere maybe found within state legal traditions across the United States. Most prominent is the example of Louisiana, where state law is based on civil law as a result of Louisiana’s history as a French and Spanish territory prior to its purchase from France in 1803. Many of the southwestern states reflect traces of civil law influence in their state constitutions and codes from their early legal heritage as territories of colonial Spain and Mexico. California, for instance, has a state civil code organized into sections that echo traditional Roman civil law categories pertaining to persons, things, and actions; yet the law contained within California’s code is mostly common law.

And while Blackstone prevails as the principal source for pre-American precedent in the law, it is interesting to note that there is still room for the influence of Roman civil law in American legal tradition. The founding fathers and their contemporaries educated in the law knew not only the work of English jurists such as Blackstone, but also the work of the great civil law jurists and theorists. Thomas Jefferson, for example, owned several editions of Justinian’s Institutes, and praised the first American translated edition from 1812, with its notes and annotations on the parallels with English law, for its usefulness to American lawyers. Indeed, a famous example of its use is the 1805 case of Pierson v. Post, in which a New York judge, deciding on a case that involved a property dispute between two hunters over a fox, cited a Roman law principle on the nature and possession of wild animals from the Institutes as the precedent for his decision. Today Pierson v. Post is often one of the first property law cases taught to American law students. United States v. Robbins, a 1925 California case that went to the Supreme Court and paved the way for the state’s modern community property laws, was based upon a concept of community property that California inherited not from English common law but from legal customs of Visigothic Spain that dated to the fifth century CE. Cases such as these illuminate the rich history that unites and divides the civil and common law traditions and are a fascinating reminder of the ancient origins of modern law.

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