Roman law is the legal system of both the Roman Republic and the Roman Empire, from its earliest days to the time of the Eastern Roman Empire, even to the time of the Emperor Justinian I after the fall of Rome itself.
Roman law is the foundation of many legal systems of the world.
Roman law has its beginnings in the code known as the Twelve Tables (449 BC). From there Roman law became highly advanced for its time, developing over the centuries many of the legal institutions that are taken for granted today.
For example, Roman law developed the differentiation between contract and tort. Previously (as in ancient Greek law), contract violations were simply a kind of tort. Also, the differentiation between possession/possessio (which is a factual state: someone has something) and ownership/dominium (which is a right; later formulated as the right to do whatever one wishes with something) was developed in Roman law, most visible in the rei vindicatio, the action of the owner against the possessor to release a piece of property. Finally, the origins of today's concept that contracts are valid when there is a meeting of the minds can be found in the Roman rules.
Roman law also developed the concepts of one law for the citizens and another law for foreigners – the beginnings of private international law.
Roman law speaks volumes of the Roman mindset in general. Praetorial intervention ensured that the law could adapt to the changing needs of a rapidly expanding empire. This was achieved, however, under the guise of consistency and attachment to traditional values. The Praetor "changed" the law not by rewriting it but by offering new remedies to cope with new problems. This attachment to the past and suspicion of change is arguably characteristic of Roman thinking.
The Emperor Theodosius I produced a compilation of Christian Imperial law in AD 438 under the title Codex Theodosianus. The compilation included only edicts on various topics issued by emperors themselves from the time of the first Christian emperor Constantine [AD 306-337]. In the next century, the Emperor Justinian arranged for the re-organisation of most of Roman law in his four-part Corpus Iuris Civilis (Body of Civil Law), the greatest achievement in the codification and preservation of Roman law. The first portion, the Codex, contained numerous laws of emperors ranging as far back in time as the emperor Hadrian (AD 117-138). The second portion, the Digesta or Pandectae, was an enormous collection of extracts from learned juristic scholars' discussions (some as old as the Roman Republic) of various legal problems which, though purely academic in nature had earned the force of law. This section became a fifty book set that took three years to compile and was completed in 533. The Emperor also ordered the production of a textbook, Iustiniani Institutiones ('The Institutes of Justinian: a beginner's textbook, still as or more useful than its modern counterparts), during the early 530s. It was intended as an overview of Roman law for legal students and consisted of just four books. Its contents were granted the force of law, an unusual distinction for a textbook. The fourth and least important portion of the Corpus Iuris Civilis were the Novellae Constitutiones, the "New Laws," produced after the promulgation of the Codex Iustinianus. They contain legal material enacted subsequent to the publication of the rest of the Corpus, which had been intended, unrealistically, to be the final and perfect statement of Roman legal development. In addition, they were published in Greek, the language of Justinian's early Byzantium (and the whole of the Roman east throughout imperial history) in contrast to the rest of the Corpus' Latin. After the completion of the project, no further laws were (supposedly) needed and commentary upon the whole of the Corpus Iuris Civilis was forbidden. Of course, the Novellae themselves prove that Law continued to thrive and no legal system can ever be fully complete. The Corpus has been called the most influential law work ever written as it has been on the reading list for legal students in countries using Civil law for nearly 1500 years so far.
Roman law methods are divided three types of process that refers to the governmental periods of Rome (Roman Kingdom, Roman Republic and Roman Empire (the principate and dominate)). The "legis actiones"-period during the kingdom and the first part of the republic. In the 3rd century BC the Roman law process had evolved into the "formulas"-period which continued until the first part of the principate. And finally the "cognition"-period during until the end of the dominate.
- Peter Stein, Roman Law in European History, Cambridge University Press, 1999 (ISBN 0521643724).
- Andrew Borkowski, Textbook on Roman law, Oxford University Press, 2nd Ed. (ISBN 1-85431-642-7).
- Barry Nicholas, An Introduction to Roman Law Clarendon Press, 1962 (ISBN 0-19-876063-9).
- Jill Harries, "Law and Empire in Late Antiquity" Cambridge, 1999 (ISBN 0-521-41087-8).
The first is suited to someone more interested in the impact of Roman law on later systems and the detail on the law itself here is comparatively brief. The second offers the most accessible and detailed information. The third offers many interesting insights and extra detail but occasionally fails to include areas that can be found in Borkowski's work. The fourth is an excellent historical survey of later legal development confined in the main to the fourth century AD.