Civil law, body of law based on Roman law, dealing with private rights claims between individuals, as opposed to criminal law (offenses against the state). After the fall of the Roman Empire, the customs of the ruling tribes developed into customary law throughout most of continental Europe, including England. Roman law was rediscovered in the 12th century, and European jurists began to codify the existing legal systems with Roman additions. The Corpus Juris Civilis of Justinian I (6th century) was of special importance for these evolving legal systems. The development of civil law was further enhanced by the Code Napoleon (1804), which gave France a unified national code. Other countries, mainly in continental Europe and Latin America, followed the French lead. Codes of civil law countries state general legal principles that courts must interpret in the light of particular cases. In common law countries such as Great Britain, Canada, and the United States (excluding Louisiana), the courts are bound by previous decisions (the rule of precedent). Trial by jury and the law of evidence are key features of legal practice in common law countries; they have no counterpart in civil law.