Roman law is the legal system of ancient Rome, and the legal developments which occurred before the 7th century AD — when the Roman–Byzantine state adopted Greek as the language of government. The development of Roman law comprises more than a thousand years of jurisprudence — from the Twelve Tables (c. 439 BC) to the Corpus Juris Civilis (AD 529) ordered by Emperor Justinian I. This Roman law, the Justinian Code, was effective in the Eastern Roman (Byzantine) Empire (331–1453), and also served as a basis for legal practice in continental Europe, as well as in Ethiopia, and most former colonies of European nations, including Latin America.

Historically, "Roman law" also denotes the legal system applied in most of Western Europe, until the end of the 18th century. In Germany, Roman law practice remained longer, having been the Holy Roman Empire (963–1806); thus the great influence upon the civil law systems in Europe. Moreover, the English and North American Common law also were influenced by Roman law, notably in the Latinate legal glossary — stare decisis, culpa in contrahendo, pacta sunt servanda. In contrast, Eastern Europe, though influenced by the Byzantine Empire, was not much influenced by the jurisprudence of the Corpus Juris Civilis; however, they did accept the Roman influence of the Farmer's Law.

Roman or Romans may refer to:

Note: the following entries are arranged in an etymological tree.

The Law is a system of rules and guidelines which are enforced through social institutions to govern behavior. Laws are made by governments, specifically by their legislatures. The formation of laws themselves may be influenced by a constitution (written or unwritten) and the rights encoded therein. The law shapes politics, economics and society in countless ways and serves as a social mediator of relations between people.

A general distinction can be made between civil law jurisdictions (including Canon and Socialist law), in which the legislature or other central body codifies and consolidates their laws and common law systems (including Sharia), where judge-made binding precedents are accepted. In some countries, religion may inform the law; for example, in jurisdictions that practice Islamic law, Jewish law or Canon law.

The adjudication of the law is generally divided into two main areas. Criminal law deals with conduct that is designated dishonest by the government and in which the guilty party may be imprisioned or fined. Civil law (not to be confused with civil law jurisdictions above) deals with disputes between individuals or organizations, in which compensation may be awarded to the wronged litigant.