Roman law was the law of the city of Rome and subsequently of the Roman Empire. The influence of Roman law on modern legal systems has been immense: several legal systems of the world (including the civil law system of Europe) have been shaped significantly, directly or indirectly, by the concepts of Roman law.

The development of Roman law comprises more than a thousand years of jurisprudence which developed in different phases. A high-watermark in Roman jurisprudence was the Corpus Juris Civilis (529-34 AD), drafted under the direct guidance of Emperor Justinian I (c.482-565 AD). The Corpus Juris Civilis is a remarkable legacy from a remarkable era in legal history.

Five and a half centuries after the death of Emperor Justinian and centuries after the decline of the Roman Empire, the ‘jurisprudence’ of Rome was ‘revived’ — partly by being studied in the universities of Northern Italy from the 11th century onwards. Nicholas, in his book, An Introduction to Roman Law, noted that this phase of Roman law “gave to almost the whole of Europe a common stock of legal ideas, a common grammar of legal thought and, to a varying but considerable extent, a common mass of legal rules”.1

Although many have argued that England stood out against the ‘reception’ or ‘revival’ of Roman law and retained its own common law, it is accepted now that the common law, too (and, as a consequence, the law of Ireland), has been, to a considerable extent, influenced by Roman law.

Today, there are two great legal systems of European origin in the world — the common law of England and the civil law of continental Europe shaped largely by the ‘revived’ Roman law.  The common law is the basis of the legal systems of most English-speaking nations. The civil law is the basis of the legal systems of countries on the continent of Europe and countries in South America and elsewhere. The other non-European legal systems, the Hindu and the Mohammedan, are largely religious based but have ‘imported’ aspects of the common law and civil law into commercial transactions.

Students of law will be familiar with the concepts of, and distinctions between, public law and private law.  Public law relates to the regulation of the state, constitutional law being a branch of public law. Private law regulates legal relationships among individuals, with Roman law having the greatest influence in this sphere.  This chapter is, in the main, confined to the private law sphere.

Phases of Roman history

From around 510 BC, the Roman Republic developed as a small city-state.  By 272 BC, following a period of territorial expansion, Rome’s control over Italy was almost complete.  In two wars (264-241 BC and 218-201 BC) Carthage, a rival for the Central Western Mediterranean, was eventually defeated.  Subsequently Rome was at war with the East. Territorial expansion in the 2nd century BC changed the face of Italy from small farming holdings to large estates with slave labour. Over a period of time, a professional army became mobilised. This enhanced the power of ambitious generals who set a pattern of throwing Rome into civil wars that contributed to the downfall of the Republic.

After much strife, a period of peace and stability commenced c. 27 BC and Octavian, known as Augustus, restored constitutional government and the Empire took shape. Around this time, all the territory surrounding the Mediterranean and territory far beyond the Mediterranean was part of the Roman Empire. By the 1st century AD, the Roman Empire extended from Britain to Dacia (equivalent to modern Romania). However, Rome failed to hold the territory north of the Danube occupied by the Germanic peoples. In later times, the Germanic peoples were to overthrow the Roman Empire.

Sources and forms of Roman law

In terms of sources of written law, the Twelve Tables (c.451 BC) were both a ‘statute’ (lex) and a code — an early example of the codification of Roman Law.  The law of contract — deposit and sale, elements of which are termed the law of obligations — whereby private agreements are recognised by the state and legally enforceable, can be traced back to the Twelve Tables. The concept of the consensual contract of sale (emptio venditio) was one of the great Roman ‘inventions’.

‘Magisterial’ law was developed by the edicts of the magistrates and above all by the decisions of the urban praetor. The day-to-day functions of the praetor were to grant remedies in individual cases.  Professor John M. Kelly has noted that the praetor was “the absolute uncontrolled master of civil legal process”.2 All civil actions were initiated before the praetor and it was he who decided if a matter would go before a judge (iudex). There was no appealing the praetor’s decision.  Subsequently, at the height of the Roman Empire, the praetor would hear the whole case in person or appoint a delegate to do so. (This aspect of the law of Rome has no modern equivalent as many democracies have adopted the doctrine of the separation of powers — with a ‘separation’ between the executive, legislative and judicial branches of government.)

The praetor also presided over criminal proceedings. The praetor could appoint judges (who acted as modern-day jurors) who decided on the guilt or innocence of the party charged. The legacy of this Roman court procedure was the practice of referring disputed legal claims to a iudex (judge). The judge heard the evidence of the respective parties and the submissions of the oratores (the advocates) and then made a binding decision. If the claim was successful, the successful claimant could seize the person or property of the respondent party.  So, the concept of a plaintiff, a defendant and an impartial judge (and indeed a jury) may have had its earliest manifestation in Roman law.

Jurists in the Roman era left a significant legacy in the form of legal commentaries and treatises.  The jurists gave legal opinions at the request of clients and advised the praetors.  Some also held judicial or administrative positions. The jurists were practical persons concentrating on individual cases upon which they had been consulted — hence their description as iuris consulti, (i.e. persons consulted about the law).

There were three broad categories of Roman law. The ius civile was the law which emanated from statutes (leges), plebiscites, decrees of the senate, enactments of the emperor and from the authority of the jurists, and   originally was the body of law that applied to the citizens of Rome. The ius gentium referred both to the body of law that applied to ‘foreigners’ in their engagement with the citizens of Rome and to the law governing the relations of Rome with other states. The ius commune was the general law common to all, the law which was binding on all peoples, including Roman citizens.

The tabelliones (later notarii), sometimes translated into English as ‘notaries’, drafted Roman legal documents. Following the edict of Emperor Antonius Pius (86-161 AD) a tabellio became entitled to receive a salarium (salary/fee).  Justinian introduced new regulations for the Corpus Juris aimed at giving the profession of tabellio a systematic sense of organisation. In another evolution, the notarii became secretaries to the authorities, including the Emperor. Under the reign of Charlemagne (768 to 814 AD) the instruments drafted by the notaries acquired the same force and effect as a conclusive judgment. The notary profession flourished during the Renaissance, further endowed by Napoleon in March 1803 with functions and duties that survive largely today  on the continent of Europe and  in countries around the world with a civil law  inheritance.

Justinian’s Digest, Institutes, and Codex

Justinian became emperor in 527 AD and, incidentally, was reputed to be the last Roman Emperor to speak Latin as a first language.  Justinian’s ambition was to revive the Empire’s greatness (renovatio imperii) and re-conquer certain territories of the Western Roman Empire.  He ordered his chief jurists to extract the best and most reliable sections of the earlier Roman texts for inclusion under appropriate headings in a digest.  All prior texts were to be destroyed throughout the Empire to eliminate discrepancies. The Digest was completed by 533 AD.

A mosaic depicting Emperor Justinian flanked by Archbishop Maximian, other court officials, and Praetorian guards. The work, created sometime before 547, was created by the Master of San Vitale and is located at the Basilica of San Vitale in Ravenna.

Justinian also directed his jurists to prepare a textbook for law students called Justinian’s Institutes which was also completed by 533 AD. The following year Justinian’s jurists completed a final version of all the Imperial statutes known as the Codex (Code). The texts known as the Digest, the Institutes and the Codex subsequently became generally known as the Corpus Juris Civilis (body of civil law).3 Set out below is an extract from the Institutes, translated by Thomas C. Sandars,4  which demonstrates a remarkable elegance of expression and nobility of legal thought pertaining to the science of the law — jurisprudence. The opening words of Liber Primus (first book), offering the definition of ‘justice’, or as some might describe it, the ideal law, were remarkable and stand the test of time.

Liber Primus: Tit. I. De Justitia et Jure

Justice is the constant and perpetual wish to render everyone his due.

1. Jurisprudence is the knowledge of things divine and human: the science of the just and the unjust.

Having explained these general terms, we think we shall commence our exposition of the law of the Roman people most advantageously if our explanation is at first plain and easy, and is then carried on into details with the utmost care and exactness. For, if at the outset we overload the mind of the student, while yet new to the subject and unable to bear much, with a multitude and variety of topics, one of two things will happen — we shall either cause him wholly to abandon his studies, or,  after great toil, and often after great distrust of himself (the most frequent stumbling block in the way of youth), we shall at least conduct him to the point, to which, if he had been led by a smoother road, he might, without great labour, and without any distrust of his own powers, have been sooner conducted.

2. The maxims of the laws are these: to live honestly, to hurt no one, to give everyone his due.

3. The study of law is divided into two branches; that of public and that of private law. Public law is that which regards the government of the Roman Empire; private law, that which concerns the individuals. We are now to treat of the latter, which is composed of three elements, and consists of precepts belonging to natural law, to the law of nations and to the civil law.

In Roman jurisprudence, and more particularly during the ‘revival’ of Roman law, ius naturale developed as the natural law. It included everything beyond the power of human law-making. The idea of ‘natural law’ (as we know it today) was influenced by and developed from the ius naturale which, over time, came to include the concept of fundamental human rights, i.e. those rights inherent to man and which cannot be taken away by human law. The writings of Cicero (106-43 BC), (court advocate and politician before the Christian era) influenced the development of the ius naturale. As stated, the expression of this law in turn influenced the natural law doctrines of the medieval Roman Catholic Church and what have been described as ‘secularised’ natural law theories.  In his De Legibus, Cicero writes:

True law is right reason in agreement with nature, diffused among all men; constant and unchanging, it should call men to their duties by its precepts, and deter them from wrongdoing by its prohibitions ….

To curtail this law is unholy, to amend it illicit, to repeal it impossible; nor can we  be dispensed from it by the order either of the senate or of popular assembly; nor need we look for anyone to clarify or interpret it; nor will it be one law at Rome and a different law at Athens, nor otherwise tomorrow than it is today; but one and the same law, eternal and unchangeable, will bind all peoples and all ages; and God its designer, expounder and enacter [sic], will be as it were the sole and universal ruler and governor of all things; ….

The term ‘civil law’ comes from ius civile. This is what we would designate as ‘positive law’ today.  In the context of the civil law, the Institutes state:

Every community governed by laws and customs uses partly its own law, (the civil law — the law of the particular state) and partly laws common to all mankind.5

Ius gentium referred to the law of nations and also to the laws common to all mankind. These were human-made laws but, as stated, “common to all mankind”. Today, we would designate ius gentium as (in part) ‘international law’.  Rules of diplomacy and state relations were governed by the ius gentium. Laws relating to commercial trade and commercial practices were also comprised in the ius gentium — what we call ‘private international law’ today.

The Roman law of ‘things’ (res) — economic assets — was divided into the law of property (that is, ‘things’ in a restricted sense), the law of succession and the law of obligations. Today, this division of the law is a cardinal feature of the modern civil law.

The law of sale is set out in Justinian’s Institutes (Liber Tertius, Tit. XXII De Consensu Obligatione). The Romans became great merchants — men of business — and built a business empire which required law to regulate their transactions. This extract below from the Institutes refers to the law of obligations:

Obligations are formed by the mere consent of the parties in the contracts for sale, or letting to hire, of partnership, and of mandate. An obligation is, in these cases, said to be made by the mere consent of the parties; because there is no necessity for any writing, nor even for the presence of the parties; nor is it requisite that anything should be given to make the contract binding, but the mere consent of those between whom the transaction is carried on suffices.

‘Reception’ or ‘revival’ of Roman law

Roman law enjoyed a renewal during the renaissance of learning in Europe from about the 11th century onward. This is sometimes described as the ‘reception’ of Roman law. Paul Vinogradoff, in his celebrated work, Roman Law in Medieval Europe, posed the question of why the so-called ‘reception’ of Roman law became so significant in the period from the eleventh to the eighteenth centuries in the following terms:

Within the whole range of history there is no more momentous and puzzling problem than that concerned with the fate of Roman law after the downfall of the Roman State. How is it that a system shaped to meet certain conditions not only survived those conditions but has retained its vitality even to the present day, when political and social surroundings are entirely altered? Why is it still deemed necessary for the beginner in jurisprudence to read manuals compiled for Roman students who lived more than 1,500 years ago? How did it come about that the Germans, instead of working out their legal system in accordance with national precedents and with the requirements of their own country, broke away from their historical jurisprudence to submit to the yoke of bygone doctrines of a foreign empire?6

One explanation for the ‘reception’ of Roman law, according to Professor Alan Watson, is related to the concept of ‘legal borrowing’ — the ‘legal transplant’.7 When lawyers and courts seek a solution and none is available within their own system, the thinking lawyer can find a precedent elsewhere. There were also the law teachers initially at the renowned universities of Northern Italy who studied the legal writings of the Roman era and imbued generations of lawyers and high-ranking administrators with a respect for Roman law. This facilitated the gradual assimilation of Roman law into local customary law.

The noted teacher Irnerius (c.1055-c.1130), who taught at Bologna, expounded the Corpus Juris Civilis clause by clause. Irnerius, his peers and his successors became known as the ‘Glossators’.  Roman law became a popular subject of study at the universities of Italy.

Roman law and the common law

Julius Caesar arrived in Britain in 53 BC. Britain was a Roman province for three and a half centuries. Many thousands of Roman soldiers were garrisoned in Britain over that time.  The Roman soldiers were withdrawn c.410 AD  because they were required to defend bases in Italy against invasions.

Roman law was not ‘received’ in England — the home of the common law — to the extent that it was on the continent of Europe. Nevertheless, it would be totally incorrect to argue that Roman law did not have a significant influence in the development of the common law. There is evidence of the direct citation of Roman law in the common law courts — a practice that fell into disuse in the course of the 14th century.8 The citation of Roman law in such courts could not but contribute to the development of the common law. It has been argued by legal scholars that far more important than the reception of Roman ‘rules’ by English law was “the influence of the Roman law on the English way of looking at the law, on English jurisprudence and on English law writing”.9

Latin, for a time, was the language of official documents in England and in the courts. It would only be natural then that there would have been a Roman law influence on early English law.  Dr. Perch H. Winfield has acknowledged that in the context of land law, the grants of land to private individuals ‘unclogged’ by the native ‘folkright’ can be linked to the Roman conception of ownership.10  It has also been argued that the law of wills probably had a Roman origin by way of ecclesiastical law.11

Legal scholars now have come to the conclusion that the concept of trial by jury, long regarded as of Anglo-Saxon origin, is in fact of Roman origin.12

The common law that shaped American law and what are described as other ‘common law jurisdictions’ contains many principles that have a Roman law origin.  The statement “by natural law all men are equal” is from the pen of Ulpian,  a noted jurist whose major legal texts date from c.211 to 222 AD; another notable principle from Ulpian is the celebrated concept expressed in the words ‘justice is the constant and perpetual wish to render everyone his due’. The maxim and legal concept of volenti non fit injuria (the voluntary assumption of risk) is again another principle of law direct from Ulpian. A significant amount of the writings of Ulpian were ‘codified’ in Justinian’s Institutes.

There are other more specific contributions that Roman law made to the law of England — the home of the common law. The principles enshrined in what is termed Habeas Corpus — a remedy where a person is detained unlawfully — and several principles of the law of torts are of Roman origin.  The fundamental right encapsulated in the expression “every man’s house is his castle”, although claimed to be of Anglo-Saxon origin, is of Roman origin.  Justinian’s Digest prohibits forcing a man from his house and compelling him to court without lawful justification — a principle articulated by Cicero.13

There is considerable evidence that the advent of Christianity and the new religion’s association with Rome and the Canon Law had a significant impact on the development of native ‘law’ in Britain.  Pope St. Gregory the Great, “a Roman of the Romans”, sent St. Augustine to Britain in 595 AD where he established his episcopal seat at Canterbury (597 AD). St. Augustine and his monks were familiar with the Justinian law. For the clergy the law was the canon law, influenced and intertwined with Roman law. The law was frequently committed to paper by the regal authorities in the pre-Norman period by those familiar with the Roman codifications.

The Norman conquest eventually brought a system of law and order to Britain. William the Conqueror’s victory at the Battle of Hastings in 1066 led to systematic administration.  William was ably assisted by Lanfranc, the lawyer who had studied and taught Roman law at Pavia in his native Italy, sometimes described as William the Conqueror’s prime minister. Lanfranc had previously lectured at a school in Normandy. Lanfranc became Archbishop of Canterbury in 1070. Pollock and Maitland, the noted English legal historians, noted the significance of Lanfranc and continued:

The Norman Conquest takes place just at a moment when in the general history of law in Europe new forces are coming into play.   Roman law is being studied, for men are mastering the Institutes at Pavia and will soon be expounding the Digest at Bologna; Canon law is being evolved, and both claim a cosmopolitan dominion.14

Roman law authorities, according to legal historians, “were habitually cited in the common law courts of Britain and relied upon by legal writers, not as illustrative and secondary testimonies, but as primary and practically conclusive”.15

Over time, there developed in England a dislike of the study of civil law, with its Roman influence.16 The Church too became concerned with the development of secular jurisprudence. The Church, for its own purely theological reasons, appeared to become lukewarm on the development of Roman law in Britain.

So Roman law fell into some disfavour with the authorities long before the Reformation. However, the great writers of law in Britain, such as Ranulf de Glanvill (1130-1190), Chief Justiciar of England, and Henry de Bracton (c.1210-1268), a member of the clergy and a royal judge, were steeped in the principles of Roman law and not only influenced successive legal writers but were often cited in court and thus indirectly shaped judge-made law in England. Bracton in his celebrated treatise De legibus et consuetudinibus Angliae (On the laws and customs of England) incorporated either directly or indirectly many passages from the Justinianic compilations of the sixth century (Digest, Institutes and Code) which from the eleventh century had a significant influence and currency in Western Europe.17 Professor Osborough has noted that such aspects of Roman law that remain secreted within common law doctrine today owe their place there in a great number of instances to the legacy of Bracton.18

Pope Innocent III (Pope 1198-1216) compelled King John (1166-1216) to accept Cardinal Stephen Langton, a Doctor of Laws from the University of Bologna, as Archbishop of Canterbury (1207). John then attempted to seize Church property as a form of retaliation. It is accepted that Langton joined with the barons in drafting the celebrated charter of Magna Carta (1215).  However, many scholars believe that Stephen Langton was the principal draftsman and that Magna Carta’s source and inspiration were not the English feudalistic institutions, but rather  the universality of the law proclaimed by the Roman legal tradition.19 In this context, there is also the Great Charter of Ireland (Magna Charta Hiberniae) (1216) issued by King Henry III  which was the application of the original Magna Carta to Ireland with appropriate substitutions such as ‘Dublin’ for ‘London’ and ‘Irish Church’ for ‘Church of England’. Inherent in these Charters was the concept of the universality of the law — a law common to all — which was a feature of canon law, being one of the sources of the common law.

As stated earlier, it is considered that the principles of ‘equity’ ameliorating the harshness in individual cases of generally applicable written law were inspired by Roman law.  The Chancellors of England were up to the time of St. Thomas More (Lord Chancellor 1529-1532) ‘ecclesiastics’ or ‘churchmen’. The equitable jurisdiction of the court resembled what the Romans termed aequitas, meaning what is fair or conscionable, a concept to be contrasted with a ‘written’ law, referred to as lex (plural, leges). Professor John M. Kelly has argued that a “theory of equity” “formed part of the Romans’ intellectual armoury”, and equitable values were in fact introduced into Roman law via the jurisdiction of the praetor.20 The influences of the ius civile and of the canon law (canon law being influenced by Roman law) on the English doctrines of equity are manifest. Equity was a canonical concept to alleviate the rigour of the law.21 The doctrines of uses, laws relating to trusts, legacies and the equity of redemption in the law of mortgages may be traced to Roman and canonical concepts.

Coke (1531-1634), a Chief Justice of the English Court of King’s Bench and a noted jurist and writer, stated that the merchant law (lex mercatoria) was to be held as  part of the law of England.22  Blackstone (1723-1780),  judge, jurist  and Vinerian professor of English law at Oxford University, in his celebrated Commentaries stated that “the custom of merchants or lex mercatoria which, however different from the general rules of the common law, is yet ingrafted into, and made a part of it”.23 Re has noted that the ius gentium of merchants ultimately governed all commercial transactions in Britain.24

Lord Mansfield (Lord Chief Justice of the King’s Bench, 1756-1788), described as the “father of modern mercantile law”, who had studied Roman law at the University of Leiden and who served for a long period  as Chief Justice, developed a system of commercial law based on Roman law.[xxv] The law of admiralty in Britain was closely aligned with the lex mercatoria; thus, the  principles of Roman law  are equally reflected in this  branch of the law.

Palmer noted that many basic principles of American law (like English law) have Roman origins —  such as the law of “adverse possession, bailments, carriers and innkeepers, contracts, the descent of property, easements, legacies and wills, guardianship, limitation of actions, marriage, ownership and possession, conveyances, sales trusts, warranties, partnerships, and mortgages”.26

The Act of Union 1800 united the Kingdom of Great Britain with the Kingdom of Ireland to create the United Kingdom of Great Britain and Ireland. Article 73 of the 1922 Constitution of Ireland provided for the continuance in the new Irish Free State (subject to the 1922 Constitution) of laws immediately in force prior to the enactment of the 1922 Constitution.  Article 50 of the Constitution of Ireland 1937 provided similarly and thus the law in force in the United Kingdom of Great Britain and Ireland immediately before the enactment of the 1922 Constitution — with its Roman law influences —  became part of the law of Ireland.

Professor W. N. Osborough stated27 that it is noteworthy that the rules of Roman Law have been prayed in aid by the Irish judicial bench in a diverse  range of contexts – “rights affecting  rivers and lakes; domicile; subrogation; ‘possession’ in larceny; donations mortis causa; alluvion; military wills; proprietary rights in domesticated animals and captive fish; specificatio; and title by occupancy”. Professor Osborough also noted that in a number of cases in Ireland judges resorted to the texts of Roman law considered in the foregoing paragraphs.


Charles P. Sherman of the Faculty of Law, Yale University, in his perceptive article, “The Romanization of English Law” (1914),28 summed up the contribution of Roman law to English law.  As stated above, Article 73 of the Free State Constitution (1922) ordained that the whole corpus of the existing (English) law  was carried over  from the former order, and continued in force in the new Free State of Ireland  except to the extent that inconsistencies between  the former law and the new Constitution might emerge. Accordingly, we may interpret what the author has stated as being applicable also to Irish law. The following was Sherman’s conclusions in 1914:

But the Romanization of English law has not been small; a summary of specific contributions from Roman to English law [and hence Irish law] reveals the great indebtedness of our law to the law of Rome. Most of the basic principles of the English law of admiralty, wills, successions, obligations, contracts, easements, liens, mortgages, adverse possessions, corporations, judgments, evidence, come from the survival of the revival of Roman law in English law. The fundamental conceptions of Habeas Corpus and trial by jury as well as many principles of the law of torts are of Roman origin. That dearly cherished principle and familiar palladium of English liberty, — “every man’s house is his castle” — is not of Anglo-Saxon origin, but of Roman origin. It is first found in the era of the Roman Republic, when the barbarians in Britain or Germany had no houses worthy of the name: Digest 2, 4, 18 expressly forbids forcing a man from his house to drag him to court, thus re-affirming Cicero’s statement of the same prohibition. Finally … our statutes resemble somewhat in form the Constitutions of the Roman Emperors, and our reported cases [resemble] the Responsa Prudentium as contained in the Digest.

Roman law was not confined in its genesis to the City of Rome or the Italian peninsula but to the genius of minds from many lands, and it has left a great legacy in the legal systems of the world. The Emperor Justinian, building on earlier jurists, codified in a structured written form a sophisticated system of law by means of the Digest, Institutes and Codex. This codified system of law has influenced most of the civil law around the world.  The concepts inherent in the legal order comprised in the ius naturale and ius gentium, intended to extend beyond national borders, are today the cornerstones of human rights law and international law throughout the world. The influence of Roman law on the development of the common law is equally undeniable.