Roman law

Lore & Background

The first legal text of Roman law is the Law of the Twelve Tables, dating from the mid-fifth century BC. According to tradition, after political struggle, the plebeians convinced the patricians to send a delegation to Athens to copy the Laws of Solon, and also to other Greek cities. In 451 BC, ten Roman citizens (decemviri legibus scribundis) were chosen to record the laws, producing a set of laws inscribed on ten tablets, with two additional tablets added in 449 BC. Modern scholars challenge the accuracy of Roman historians, doubting that a second decemvirate occurred and questioning whether an official delegation was sent to Greece, suggesting instead that Romans acquired Greek legislation from Greek cities of Magna Graecia.

Reader's Guide

Roman law's most important contribution to European legal culture was the emergence of a class of professional jurists and a legal science, achieved by applying Greek philosophical methods to law. The jurists worked in various functions, including giving legal opinions and advising magistrates. During the classical period (first 250 years of the current era), Roman law and legal science reached their greatest sophistication. After the dissolution of the Western Roman Empire, Roman law remained in effect in the Byzantine Empire, and from the 7th century onward, the legal language in the East was Greek. Roman law influenced English and Anglo-American common law, notably in its Latinate legal glossary, and Eastern Europe was influenced by the jurisprudence of the Corpus Juris Civilis, including in medieval Romania.

Did You Know?

• The original text of the Twelve Tables has not been preserved; the tablets were probably destroyed when Rome was conquered and burned by the Gauls in 387 BC.
• The Lex Aquilia of 286 BC may be regarded as the root of modern tort law.
• Around 300 BC, Gnaeus Flavius is said to have published the formularies containing words spoken in court to begin a legal action, which had previously been secret and known only to priests.
• The jurist Sextus Pomponius said that at the beginning of the city, the people began without any fixed law, and all things were ruled despotically by kings.

The Roman Blueprint: Ius Gentium

The Roman Empire left one of the most consequential intellectual legacies in the long history of interstate relations: the concept of ius gentium. By drawing on the Greek idea of natural law, Roman jurists fashioned a body of rules they regarded as universal in scope. This framework did not govern the internal politics of Rome so much as it addressed the legal standing of non-citizens residing within the city and the interactions between those foreigners and Roman citizens. Crucially, the Roman law of nations operated at the level of individual persons rather than at the level of sovereign political entities, a distinction that sets it apart from the modern international legal order. Despite that limitation, ius gentium became the conceptual seed from which later scholars would grow the entire edifice of international law. Hugo Grotius and Emer de Vattel both built upon the Roman and medieval vocabulary when they articulated their own theories of the law of nations, ensuring that the Roman formulation remained embedded in the discipline's very name and structure for centuries.

Treaties Before the Nation-State

Long before the modern vocabulary of international law existed, polities across the ancient world were already negotiating binding agreements with one another. Among the earliest surviving examples are the peace treaties struck between the Mesopotamian city-states of Lagash and Umma, dating to roughly 3100 BCE, and the famous accord concluded in 1279 BCE between the Egyptian pharaoh Ramesses II and the Hittite king Ḫattušili III. These pacts demonstrate that the impulse to formalize interstate conduct is not a modern invention but stretches back to the dawn of recorded civilization. In Ancient Greece, a parallel tradition flourished as city-states negotiated peace treaties among themselves and, on occasion, with neighboring polities outside the Greek world. From the eastern Mediterranean to East Asia, a wide array of societies developed their own practices of interstate agreement. This deep historical record underscores that the negotiation of mutual obligations between distinct political communities is one of the oldest human legal activities, predating any single civilization's claim to intellectual priority.

Naming the Discipline: From Ius Gentium to Supranational Law

The very name we use today for the law governing relations between states is a relatively recent coinage. Jeremy Bentham introduced the phrase "international law" in his 1789 work Introduction to the Principles of Morals and Legislation, deliberately replacing the older "law of nations," a term that itself translated the medieval Latin ius gentium and the French droits des gens favored by scholars like Hugo Grotius and Emer de Vattel. Bentham's definition, which focused narrowly on state-to-state relationships, has drawn criticism for excluding other actors. Lassa Oppenheim later offered the formulation most widely adopted by legal scholars: a law binding sovereign and equal states through their common consent. The discipline has since branched into distinct subfields. Public international law governs the conduct of states and intergovernmental organizations, while private international law, a term Joseph Story is credited with originating, addresses jurisdictional questions involving foreign elements in domestic courts. More recently, the concept of supranational law has emerged, exemplified by the European Union, where member states cede legislative and judicial authority to a shared supranational body whose decisions are directly effective within each member state.

Consent, Enforcement, and the Tension with Domestic Law

Unlike the legal systems of individual nations, international law rests almost entirely on the voluntary consent of its participants. There is no single, universally recognized authority capable of compelling a sovereign state to comply, which means that a government may in principle choose to ignore a treaty or violate a peremptory norm. In practice, however, such breaches tend to trigger diplomatic censure, economic sanctions, or even armed conflict, particularly when the most powerful states are involved, since they can impose heavier consequences on weaker counterparts. The absence of a final arbiter also permits states to interpret international rules in ways that suit their own interests, sometimes producing stances with significant local consequences. The recognized sources of the discipline—international custom, treaties, and general principles of law recognized across national systems—are supplemented by comity, the informal practice of maintaining good relations, though comity itself carries no binding force. Where national and international law intersect, treaties such as the Geneva Conventions obligate domestic legislation to conform, and supranational tribunals like the European Court of Human Rights or the International Criminal Court can bring international obligations directly into the domestic legal sphere.

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