A bronze tablet in the Capitoline Museums recording a law of the Senate now termed the Lex de imperio Vespasiani, establishing Vespasian in his imperial munus. Section VI states that "whatsoever he shall think likely to promote the welfare of the state ... he shall have full right (ius) and authority (potestas) to do."[1] This senatus consultum gives the emperor the absolute right to make decisions, a concept later adopted by the absolute monarchies of Europe. This legislation forestalled any questions about whether the emperor had a right to exercise the authority of the state in any way he pleased. In fact, such questioning was against the law as infringing on the emperor's rights. The death penalty was frequently invoked for such questioning, depending on the emperor (not under Vespasian, who was considered a good emperor).

Ius or Jus (Latin, plural iura)[2] in ancient Rome was a right to which a citizen (civis) was entitled by virtue of his citizenship (civitas). The iura were specified by laws, so ius sometimes meant law. As one went to the law courts to sue for one's rights, ius also meant justice and the place where justice was sought.[3]

On the whole, the Romans valued their rights as the greatest good of Roman citizenship (civitas romana), as opposed to citizenship in other city-states under the jurisdiction of Rome but without Roman rights. Outsiders (peregrini) and freedmen (libertini) perforce used Roman lawyers to represent them in actions undertaken under the jurisdiction of Roman law. Representation was one of the civic obligations (munera) owed to the state by citizens. These munera (on which account the citizens were municipes) included military service as well as paying taxes, but specialized obligations might also be associated with functions of elected offices or assigned by the government, such as paying the cost of road or aqueduct maintenance. Some of these functions were highly lucrative, such as tax collecting, since the collector collected much more than he owed the government, but for the most part functionaries were appointed for their wealth and were expected to assume the costs as their munus. If they did not, they were tried and sometimes executed. Violation of the iura of other citizens, whether in office or out, was a serious matter, for which the punishment might be death.

Meanings of ius

Ius in ancient Roman law had two principal meanings, which are still reflected in French droit, German Recht, English right and Castilian derecho.[4] Ferdinand Mackeldy, 19th-century jurist, analyzed them into two principles: ius is the law, a set of compulsory rules (Jus est norma agendi, "law is a rule of conduct"), which he called objective or positive law, and a set of possibilities to act (Jus est facultas agendi, "law is a license to act"), which he called subjective law, or duties.[5]

Aequum et bonum

Ius was defined by the jurists Publius Juventius Celsus and Julius Paulus as the aequum et bonum, "the just and the fair", or justice.[6] Jurisprudence was the art of bringing it about through application of the laws; thus ius was law in the abstract, as in the English usage of the term "the law". Iura were "the whole of laws" (iura populi Romani), not a list of all the laws, but the very principle of legality, which might be applied through this law or by the magistrates and lawyers of Rome through disputation in the law courts. Ius might be something less than the whole body of law when special fields were designated by an adjective, such as ius publicum, "public law," as opposed to private law.

The actual laws (leges), or written statutes, were only the specific tools through which ius was applied. Ius was the law in its broadest sense or its ideal state, above and unaffected by the contingent decrees that the state happened to enact—hence the distinction between the English terms justice and legislation.

Jura et potestates

A personification of justice by Bernard d'Agesci. La justice holds scales in one hand and in the other hand a book with "Dieu, la Loi, et le Roi" (God, the Law and the King) on one page and the Golden rule on the other page.

Ius as the law was generally the domain of Roman aristocrats, from whose ranks the magistrates were chosen and who often defended clients in court. On a more practical basis, the populace of Rome daily encountered the primary meaning of ius. They understood that they had rights. Furthermore, these rights could be named and enumerated in formulae beginning with the word ius followed by a descriptive phrase, most often in the genitive case: "the right of ...."

Black defines ius in the sense of a right as "a power, privilege, faculty, or demand inherent in one person and incident upon another."[4] This power, or potestas, was a license governing behavior between persons granted by the constitution. It determined what one citizen or group of citizens could or could not do regarding another; i.e., potestas is to be translated as authority, which the possession of iura gave to individuals. One might act socially sui iuris, on one's own authority, asserting one's own right, or on behalf of another, alieni iuris, in response to a demand to serve his right by being under his authority.

This was the principle binding soldiers in the army: the consul, or a commander of some other rank, had a right to demand public service of citizens in the army, who were then under his authority. The magistrates thus had the right and power to draft men into the army at any time, but this demand was never a private affair; the males were lawfully assembled and selections were made by the commanders of the units. Typically, the right to raise a legion from a given populace for a specified purpose under the Roman Republic had to be granted by a senatus consultum, a decree of the Senate.

Similarly, under the Roman Empire the imperator ("commander") was from a legal point of view the chief magistrate whose major ius was the ordering of all public affairs, for which he could demand assistance from anyone at any time. The cynical demands of the bad emperors and the beneficial ones of the good emperors are described at great length by the historians of the empire, such as Tacitus.

The list below contains iura from different branches of Roman civilization. A ius of ancient Rome, marked by the imperial eagle, typically begins in the Roman Republic and continues through the Roman Empire. A ius of the Holy Roman Empire is marked with the double-headed eagle. The term is used in this article in the general sense to mean also the Carolingian Empire, named after Charlemagne, who had the title Holy Roman Emperor. His domain also included what is now France. Its iura reflect early Germanic laws. They are more likely to be found as legal principles in modern European countries. Iura that originated and remained primarily as canon law are marked with the coat of arms of the Holy See.


Name Literal Translation Provenience, Jurisdiction Description
ius abstinendi with potestas abstinendi supplemented by the beneficium abstinendi
Right of refusal with the power of refusal supplemented by the privilege of refusal Roman Republic on its claim based on the Twelve Tables, supplemented by the Praetorian Edict, Roman Empire In keeping with the high value placed by the Romans on family, they developed a complex system of transmitting family rights and property. That any family should disappear through lack of heirs was abhorrent.

An inheritance (haereditas) began with the rights (iura) and goods (bona) possessed by a citizen, regardless of whether there were any heirs to tenant it in the future. For the time being the citizen tenanted it. His civic duty was to find heirs (haeres). The preferred way to do this was to have children and designate them as heirs in a will (testamentum). These were voluntarii (or extranei or sui) because they had the ius abstinendi, carrying the power (potestas) of refusal. They might do that if the estate were hopelessly encumbered by debt. If the owner of the property died intestate, the law designated heirs, preferably other relatives, who were called necessarii, because they had no right of refusal.[7]

A haereditas was not automatically conferred on its heres as it is today. On the death of the testator the estate entered a pending period (delatio) during which the heirs must apply and either prove that they were qualified to be heirs or be disqualified. Voluntarii would state their intentions to accept or refuse at this time. If no qualified heirs were found, the haereditas reverted to the state, ending the family line, not considered a desirable outcome. The Praetorian Edict assigned the problem of finding heirs to the praetor, a Roman magistrate, who could appoint a manager (possessor bonorum). Before he did, the will of a pending inheritance was considered to continue the testator. A possessor assumed title as though the will were his own. He was a necessarius, but the praetor could grant him on application the beneficium abstinendi, the privilege of refusing.

After the heirs were approved the estate entered the adquisitio phase. The testamentum was now of no effect. Roman wills never extended the testator. He and any possessor were vacated at this time. Joint heirs had to be all voluntarii or all necessarii; mixed inheritance was not allowed. If no heirs had been found, the possessor kept the estate, as he had already vacated the testator.

ius abutendi
right to consume Roman Catholic Church, 14th century on Devised by Cardinal Bertrand de la Tour in support of Pope John XXII's stance in his bull, Ad Conditorem Canonum, issued 8 December 1322. The ius, also known as ius consumendi, builds on the Roman ius utendi, asserting that not only does a possessor have the right to use his property as he sees fit, but also to consume it. This ius establishes that Christ and the apostles "had the right to use, use up, sell, donate or acquire" property.[8]
ius accrescendi
right of increase, accrual, accrescence or accretion Roman Republic, Roman Empire In ancient Rome the right of accrual belonged to the joint heirs (haeres), male or female, of an expected inheritance (haereditas), whether to be transmitted by will (testamentum) or by law in the case of intestate inheritance. If any of the heirs should die or become ineligible to inherit for any reason before the death of the testator, the share of the other heirs increased by a percentage of the vacated share. This rule took precedence over any testament left by the deceased heir. Alternatives could be designated under some circumstances. There were exceptions and conditions, which required adjudication. Vacated shares for which heirs could not be found were forfeited to the government.[9]

In 9 AD the lex Pappia et Poppaea modified the Lex Julia of 18 BC (early empire), being called informally on that account the Lex Julia et Pappia Poppaea. It excluded a caelebs, an unmarried person, male or female from inheriting unless he or she married within 100 days of the death of the testator. Also excluded were orbi, or childless couples between 25 and 60 years of age for the male and 20 and 50 for the female. The intent of the law was to discourage childlessness. The emperor Justinian removed these conditions, restoring the republican form in favor of Christians who had decided to live celibate.

The ius is sometimes called the right of survivorship, the modern term for the disposition of joint property to the survivors, dating from the Middle Ages. Accrescendi, however, does not mean survivorship; moreover, the Roman use only covered the survival of joint heirs. Although general survivorship rules undoubtedly did develop from the ius accrescendi, they are not the same as the Roman.

ius ad rem, ius in personam, ius personale
right to a thing, right against a person First known in the Brachylogus, a 12th-century work purporting to give ancient Roman iura but in fact containing the iura of mediaeval kingdoms and other institutions, whose official language was Latin. There is no trace of it in antiquity. The source is believed to have been canon law. Subsequently, it became a staple of civil law in the many nations descending from the Roman Empire. The right to undertake an action against a person to compel performance of an obligated service or delivery of an owed thing.[10] The Romans would have accomplished the same result with other iura, typically under criminal law, as in a punitive action brought against a magistrate for non-performance of obligations.
ius Aelianum the jurisprudence of Aelius Not a ius, body of iura, or any type of law or any other public enactment, this phrase is the title of a missing and otherwise unknown book written under the Roman Republic. Nothing more is known of the book than that Sextus Aelius Paetus Catus, consul in 198 BC, wrote it in three parts: the laws of the Twelve Tables, an interpretation, and some cases (actiones), on which account the book was also called the Tripertita. Which if either name was original remains unknown. Whether the cases concerned the tables or were new in form or content, or just what the significance of the book in Roman jurisprudence was, are purely speculation, as no other evidence exists.[11]
ius aesneciae
principle of the first born Primogeniture was unknown to the Romans of the classical and imperial periods. It was not a right, law or legal principle associated with Rome in any way.[12] It was a principle applied to the inheritance of some fiefs among Germanic tribes in the Middle Ages and assigned the legal Latin term ius in modern times. Late Latin aesnecia or aesnetia, anglicised to aesnecy or esnecy was the condition of being the eldest born of either sex, from Old French aisne < ainznez, the condition of being ainz, first (born), as opposed to secunz.[13] Although Bede remarked that the Saxons before the conquest of Britain recognized the eldest son as the head of the family and gave him preference in inheritance, primogeniture was not made a principle of legislation until the Holy Roman Empire, when it was necessary to classify estates as divisible and non-divisible. The latter were maintained intact to support the army. They must therefore be inherited by one person (the knight), the elder by custom.[14]
ius albanagii or ius albinatus
right of alien inheritance Although this right originated in the Holy Roman Empire and existed in other reflex states, such as Bremen, it was used primarily in early France, where it became the droit d'aubaigne, droit d'aubaine or droit d'aubenage. Late Latin albinatus, "alien" and albanagium, "state of being an alien," derived from the word for alien, a person from outside the kingdom residing within it (such as a merchant).[15] In the Frankish Period they were known as Albani, Albini, Alibini, Albanici and Aubani.
  • Albanagium -- In old French law, the state of alienage, of being a foreigner or alien.
  • Albanus -- In old French law, a stranger, alien, or foreigner.
  • Albinatus -- In old French law, the state or condition of an alien or foreigner.


  • Jus bellum dicendi. The right of proclaiming war.


The jus civile and the jus gentium are distinguished as follows. All people ruled by statutes and customs use a law partly peculiar to themselves, partly common to all men. The law each people has settled on for itself is peculiar to the state itself, and is called jus civile, as being peculiar to that very state. The law that has come to be generally accepted among all men—the law that is guarded among all peoples quite alike—is called the jus gentium, "and all nations use it as if it were the law. The Roman people, therefore, use a law that is partly peculiar to itself, partly common to all men." Hunter, Rom. Law, 38.
But this is not the only, or even the generally accepted, use of the words. What the Roman jurists had chiefly in view when they spoke of jus civile was not local as opposed to cosmopolitan law, but the old law of the city as contrasted with the newer law introduced by the praetor (jus prœtorium, jus honorarium). Largely, no doubt, the jus gentium corresponds with the jus honorarium: but the correspondence is not perfect. Id. 39.
  • Jus civile est quod sibi populus constituit. "The civil law is what a people establishes for itself". Inst. 1, 2, 1; Jackson v. Jackson, 1 Johns. (N.Y.) 424, 426.
In English law: the common law, answering to the Saxon folcright, 1. Bl. Comm. 67.





Although this phrase had a meaning in Roman law that may be rendered by our expression "law of nations", it must not be understood as equivalent to what we now call "international law", its scope being much wider. It was originally a system of law, or more properly, equity, gathered by early Roman lawyers and magistrates from the common ingredients in the customs of the old Italian tribes—those being the nations, gentes, whom they had opportunities of observing[clarification needed]—to be used in cases where the jus civile did not apply; that is, in cases between foreigners, or between a Roman citizen and a foreigner. The principle upon which they proceeded was that any rule of law common to all the nations they knew of must be intrinsically consonant to right reason, and therefore fundamentally valid and just. From this it was an easy transition to the converse principle, viz., that any rule that instinctively commended itself to their sense of justice and reason must be a part of the jus gentium. And so the latter term came eventually to be synonymous with "equity" (as the Romans understood it.) or the system of praetorian law.
Modern jurists frequently employ the term ius gentium privatum to denote private international law, or that subject that is otherwise styled the "conflict of laws"; and ius gentium publicum for public international law, or the system of rules governing the intercourse of nations with each other as persons.
Ius gentium. In early Roman law, the law followed by all peoples, closely akin to the ius naturale. From this universal sense it was used more specifically to describe the international law that governed Rome’s relationship with other states. Following the works of Gaius, the term was employed more narrowly to represent the law that applied among foreigners, and among Romans and foreigners. Foreigners, and the legal relations of Romans with them, were governed by the ius gentium.


ius habendi et retinendi. A right to have and to retain the profits, tithes, and offerings, etc., of a rectory or parsonage.


Ius in re propria, denoting full ownership; distinguished from jus in re aliena, a mere easement
Ius in re inhaerit ossibus usufructarii. "A right in the thing cleaves to the person of the usufructuary".
Jus jurandi forma verbii differt, re convenit; hunc enim sensum habere debet: ut Deus invecetur. Grot, de Jur. В., 1. 2, e. 13, § 10. "The form of taking an oath differs in language, agrees in meaning; for it ought to have this sense: that the Deity is invoked."




As the Roman jurist Ulpian said, “that which nature has taught all animals”. For most writings of classical Roman law, synonymous with ius naturae. From the writings of Paul, however, the term ius naturale acquired the sense of an ideal of law, quod semper est bonum et aequum—those actions that are always fair and just. This sense is followed in the Thomist conceptions of natural law, or lex naturalis.

ius naturale est quod apud homines eandem habet potentiam. "Natural right is that with the same force among all mankind". 7 Coke, 12.


A commission from the bishop, where two presentations are offered upon the same avoidance, directed usually to his chancellor and others of competent learning, who are to summon a jury of six clergymen and six laymen to inquire into and examine who is the rightful patron. 3 Bl. Сomm. 246; 3 Steph. Comm. 517.
In international law, the right by which property taken by an enemy and recaptured or rescued from him by the fellow-subjects or allies of the original owner is restored to the latter upon certain terms. 1 Kent, Cornm. 108.
Jus publicum et privatum quod ex naturalibus praeceptis aut gentium aut civilibus est collectum; et quod in jure scripto jus appellatur, id in lege Angliae rectum esse dicitur. Co. Litt. 185. "Public and private law is collected from natural principles, either of nations or in states; and in the civil law is called 'ius', In the law of England it is said to be 'right' ".
Jus publicum privatorum pactis mutari non potest. "A public law or right cannot be altered by the agreements of private persons".


ius quo universitatis utuntur est idem quod habent privati. "The law that governs corporations is the same that governs individuals". Foster v. Essex Bank, 16 Mass. 265, 8 Am. Dec. 135.



In English law, written law, or statute law, otherwise called "lex scripta", as distinguished from the common law, "lex non scripta". 1 Bl. Comm. 62.


Ius testamentorum pertinet ordinario. Y. B. 4 Hen. VII., 13b. "The right of testaments belongs to the ordinary".
Jus triplex est—proprietatis, possessionis, et possibilitatis. "Right is threefold—of property, of possession and of possibility".



jusjurandum inter alios factum nec nocere nec prodesse debet. "An oath made between others ought neither to hurt nor profit". 4 Inst. 279.

See also


  1. ^ Hellems, Fred B.R. (1902). Lex de Imperio Vespasiani: A consideration of some of the constitutional aspects of the principate at Rome, a Thesis. Chicago: Scott, Foresman and Company. pp. 4–5.
  2. ^ The Roman alphabet had no "j"; the Romans used "i" only. In the mediaeval period Latin words beginning with i + a vowel were back-formed with a j- to represent the y- sound. Dictionaries do or do not use the j- by editorial decision.
  3. ^ Lewis & Short 2007, Jus
  4. ^ a b Black 1910, p. 675, JUS
  5. ^ Mackeldey & Dropsie 1883, p. 1
  6. ^ Berger 1953, pp. 525–526, Ius (iura).
  7. ^ Salkowski, Carl; Whitfield, E E (1886). Institutes and history of Roman private law with catena of texts. London: Stevens. pp. 857 ff.
  8. ^ Garnsey, Peter (2007). Thinking about property: from antiquity to the age of revolution. Ideas in context, 90. Cambridge; New York: Cambridge University Press. pp. 103–106.
  9. ^ Colquhoun 1851, pp. 247 ff
  10. ^ Colquhoun 1851, p. 70
  11. ^ Smith, Wayte & Marindin 1890, JUS AELIANUM.
  12. ^ Cecil 1895, p. 9.
  13. ^ Burrill 1850, AISNE.
  14. ^ Cecil 1895, pp. 27–32.
  15. ^ Burrill 1850, DROIT D'AUBAINE.
  16. ^ Dzankic, Jelena (2012). "The Pros and Cons of Ius Pecuniae: Investor Citizenship in Comparative Perspective. EUI Working Paper RSCAS 2012/14" (PDF). European University Institute. Retrieved 4 May 2018.
  17. ^ Research Centre, Ius Pecuniae (2018). "Ius Pecuniae Index". Retrieved 18 June 2018.