Chapter 3: Ius and the Oath in Rome


Parallel with díkē, the Latin ius, which is translated as “law,” has a derived verb iurare which means “to swear.” Strange though this seems from a semantic point of view, this derivation is illuminated by two complementary pieces of research:
(1) When brought into connection with Avestan yaoš- and considered in the light of its particular affinity with the verb dico (ius dicere, iudex), ius may be defined as “the formula of conformity.”
(2) A number of texts show that in Rome “to swear” (iurare) is to pronounce a formula, the ius iurandum ‘oath’, literally “a formula to be formulated,” an expression in which the very repetition brings out what is essential in the act of swearing. In fact the person swearing must repeat word by word the formula imposed on him: adiurat in quae adactus est verba.
Another Latin term connected with jurisdictional practice, arbiter, denotes, curiously enough, both the “witness” and the “arbiter.” In fact the texts show that the arbiter is always the invisible witness, who has the capacity to become, in certain determined judicial actions, impartial and sovereign iudex.


The analysis of the uses of díkē has brought out the frequency of the correlations between the Greek díkē and the Latin ius. These two terms, although different in origin, enter into parallel series: díkēn eipeîn corresponds to ius dicere; díkaios to iustus, and finally, dikaspólos corresponds more or less to iudex. A further point which may be noted is that just as díkē contrasts with thémis in referring to human as opposed to divine law, so ius is opposed to that which the Romans called fas.
What is then the real significance of this word ius? On this point we are still in the dark. We know that ius denotes “law,” but this lexical meaning does not give us the true significance of the word. And if we search for it in the relation between ius and its derivatives, we encounter a fresh problem: the verb derived from ius is iuro, but this means “to swear.” How did this verb come to diverge semantically from the basic noun in this strange way? At first sight there is an inexplicable gap between the notions of “law” and “swearing.” And yet the formal relation between ius and iurare is certain since the “oath” is called ius iurandum. What is the meaning of this expression and why do we have a future passive participle iurandum? Finally, what is the relation of ius to iuro?
The dictionary of Ernout-Meillet cites an expression ius iurare in the sense “pronounce the sacred formula which binds,” but unfortunately without giving the reference. To our knowledge such a phrase is not found. We only have the residual form ius iurandum, which leaves the gap between ius and iuro. The relation of the substantive to the verb can thus be elucidated only by appeal to a prehistoric phase, and this requires the aid of etymology. It is true that correspondents of ius have been identified, but they present a different sense. Certainly in Celtic the Irish adjective huisse < *yustiyos means “just”; apart from the final suffix this form is identical with Latin iustus. But because this gives us only a derivative and we do not know the basic noun in Celtic, this comparison tells us nothing. It is in Indo-Iranian that we find the correspondents of Lat. ius: Ved. yoḥ, Av. yaoš, which have exactly the same form.
But Ved. yoḥ means “prosperity” and Av. yaoš ‘purification’. Despite the exact correspondence of the forms the meanings expressed are different and perplexing. Nevertheless we have here one of the important correlations of vocabulary between Indo-Iranian and Italo-Celtic, one of those terms which have survived only at the extremities of the Indo-European world. The sense of yoḥ must be “happiness, health.” The word occurs only in phrases where it is coupled with śam; either śamyoḥ as a single word, or śamca yośca with the sense “happiness and health” in wish formulas such as “The happiness and prosperity which Manu has acquired by his offering, may we attain to them under your guidance, Ο Rudra” (R.V. 1, 114, 2).
Iranian, too, has preserved yaoš only in formulaic expressions in which yaoš is combined with the verb - ‘place’, to form the new verb yaoždā- ‘purify’. This is an old compound comparable to the Latin crēdō. This Avestan verb yaoždā- gave rise to numerous derivatives: an agent noun yaoždātar- ‘whose function it is to purify’; the abstract yaoždāti- ‘purification’, etc. To recover by means of these derivatives the proper sense of yaoš, which is not found in independent usage, we must assign to yaošdā-, literally “to make yaoš,” the sense “to make in accordance with prescriptions, put into the state required by the cult.” This is a condition of sacrifice: the person making the offering must make the object of oblation ritually appropriate. We have here a fundamental expression of the religious code. Each act must be ritually carried out and the object which is at the center of this operation must itself be without defect or flaw. This ritual integrity is what yaoždā- is intended to secure. In this way we can better understand the Vedic yoḥ; it is not happiness as enjoyment, but the state of “integrity,” i.e. of physical perfection as yet unaffected by misfortune or disease.
We must now pay attention to a difference of usage of *yaus between India and Iran. In Vedic yoḥ is an expression of wish: it is a term pronounced to someone to express the wish that prosperity and “integrity” may be granted him. From this it follows that yoḥ is effective in that it is a word to be pronounced. The situation of Avestan yaoš is different: here the connection of yaoš with - ‘put, make’ shows that yaoš denoted a state to be realized and not merely a word to be pronounced. Thus on the one hand the notion of *yaus is something “to be done” and on the other something “to be said.” This difference has considerable consequences in the sphere of law and ritual, where the “acts” often consist of “words.”
Thanks to Iranian and Indic we are in a position to penetrate into the prehistory of the Latin word ius. The Indo-European word *yous meant “the state of regularity, of the normality required by the rules of ritual.” In Latin this state assumes the double aspect which we have just distinguished in Indo-Iranian. The idea of ius admits of these two conditions. One is the factual situation which is denoted by the derived adjective iustus in the legal expressions iustae nuptiae ‘lawful marriage’, iusta uxor ‘legitimate wife’, that is, “conforming to the state of ius.” The other is implied in the expression ius dicere. Here ius denotes “the formula of normality,” prescribing what must be conformed to. Such is the foundation of the idea of “law” in Rome.
We thus have grounds for believing that ius, in general, is a formula and not an abstract concept; iura is the collection of legal judgments. Cf. Plautus: omnium legum atque iurum fictor (Epidicus 522-523). These iura, like the díkai or the thémistes, are formulas which embody an authoritative decision. And wherever these terms are taken in their strict sense, we find, for thémistes and díkai as for ius and iura, the idea of fixed texts, of established formulas, the possession of which is the privilege of certain individuals and of certain corporations.
Typical of these iura is the most ancient code known from Rome, the Law of the Twelve Tables, which is composed originally of judgments formulating the state of ius and using the formula ius ita esto. We find ourselves in the domain of the word, manifested by terms that agree in sense: in Latin iu-dex, in Oscan med-diss, in Greek dikas-pólos (and díkas eipeîn) and in Germanic eo-sago ‘he who says the rule, the judge’.
What is constitutive of “law” is not doing it, but always pronouncing it: ius and iu-dex bring us back to this constant combination. Along with ius the verb dicere looms large in juridical formulas, such as multam (dicere) ‘fine’, diem (dicere) ‘day for a hearing’. All this stems from the same authority and is expressed by the same turns of phrase. It was from this act of speech, ius dicere, that the whole of court terminology developed: iudex, iudicare, indicium, iuris-dictio, etc.
The sense of ius is thus defined as an expression of “law.” But we cannot yet see the direct connection between this notion and the sense taken by the verb immediately derived from it, that is, iurare. This constitutes a challenge to the interpretation of ius which has just been proposed. If it is valid, it ought to account for the relation of ius to iurare. This strange derivation points in a different direction and opens a new chapter in law. Do we find elsewhere than in Latin a connection between the notion of “law” and that of “the oath”? An investigation into this point in other languages of the Indo-European family will be necessary. The result will be negative—we may say this straight away—but it will at least serve to bring out the originality of Latin.
We have barely one example which establishes the existence of an Indo-European verb meaning “to swear”: this is the Sanskrit am- ‘swear’ which appears particularly in the imperative amī-ṣva ‘swear’ and is connected with the Greek ómnumi of the same sense. The correspondence embraces only these two terms but at least the equation is exact as regards the form and the meaning. We do not know whether this Indic verb ever existed in Iranian, but this isolated survivor suffices to attest a common term.
In Greek there is an asymmetry between the noun and the verb: “the oath” is expressed by a different word: hórkos. This word has been connected, within Greek itself, with hérkos ‘fence’, but this explanation, to say the least, is vague and unsatisfactory: the oath is conceived as a prohibition or a constraint which one determines for oneself. In any case, this is not an Indo-European equivalent but simply the result of a secondary development (cf. Book Five, Chapter Eight).
For the verbal expression “to swear” we find, apart from this, only forms limited to two languages, sometimes confined to a single language. Persian uses sōgand xurdan, literally “consume, eat the sōgand”, in Middle Persian sōkand x v ar-. This word sōkand goes back to the old Avestan saokǝnta ‘sulfur’. Thus “to swear” is “to swallow sulfur.” The expression is to be understood literally. The oath consisted of a veritable ordeal: it was the ingestion of sulfur which was supposed to test the sincerity of the person swearing the oath.
In Oscan the verb for “to swear” is known to us in the verbal form deiuatuns ‘may they swear’; the verbal root deiua- in Latin would appear as *divare, the proper meaning of which would be “take the gods to witness,” a clear expression, but one not actually found in Latin.
In other Indo-European languages the expression for the oath reflects the way in which one swears: Irish tong corresponds to the Latin tango ‘touch’; similarly in Old Slavonic prisegati and prisegnoti mean etymologically “to touch.” The primary sense of Skt. am- is “seize.” This correlation is explained by the custom of touching the object or the living thing by which one swears. For to swear by someone or something is to bring a divine curse on this person or thing if he should be false to his oath.
A final expression is common to Celtic and Germanic: Irish ōeth, Got. aiþs, which is connected with German Eid and English oath. This form is literally a verbal substantive from the root “to go.” We still have a memory of this in the German expression Eidegang, literally “the fact of going to the oath,” that is, the place of oathtaking, a survival of an ancient practice. The solemn oath comprised a number of acts, one of which was to proceed towards the place where the oath was given. One “betook oneself to the oath”: Latin ire in sacramentum, ORuss. iti na rotu ‘to go to the oath’ (cf. Book Five, Chapter Eight).
Thus we have almost as many expressions as there are languages. Only Greek and Sanskrit have an expression of Indo-European date. Thus there is outside Latin no parallel which might help us to understand the relation of ius to iurare. We must have recourse to the language itself to elucidate the origin of this expression. How was the oath taken in the Roman world? A whole series of explicit testimonies inform us about the way in which an oath was taken and enable us to understand how iurare in its given sense can be a derivative from ius. We must first read a scene from the Rudens of Plautus (ll. 1331ff.). Gripus and Labrax, who are trying to deceive each other, enter into a pact. Gripus wants to bind Labrax by an oath:
Gr. tange aram hanc Veneris ‘Lay your hand on this altar of Venus’.1333
La. tango ‘I touch it’.
Gr. “You must now swear by Venus.”
La. “What shall I swear?”
Gr. “What I am going to dictate to you.”
La. Praei verbis quidvis ‘Dictate to me anything you like in words …’1335
Gr. “Take hold of this altar.”
La. “I do so.”
Then comes the text of the oath, which is formulated by Gripus in the form in which it has to be repeated by Labrax.
Here we have, transposed into the comic vein, the hallowed mode of oath taking among the Romans. The initiator who induces the other to swear an oath must praeire verbis, he recites the text which the one who binds himself must repeat word for word while touching a sacred object; this is the essential part of the ceremony.
The solemnity of the usage is confirmed by Gellius (N.A. 11 24): the chief men of the city receive the order to swear “apud consules, verbis conceptis,” they swear between the hands of the consuls “in fixed terms,” according to a formula which they will repeat word for word.
In his Panegyric of Trajan, ch. 64, Pliny praises the scrupulous observation by Trajan of all the constitutional forms. Trajan goes to take an oath before the consul, although he could have easily been content to make others take the oath: “After all the ceremonies of the comitia were performed, see now how at the end you approach the seat of the consul; adigendum te praebes in verba… you offer yourself to be led to the words which the chiefs (principes) generally ignore except to lead others to (them) …”—and the merit of the emperor is that he goes there himself. Then the consul, seated while Trajan stood before him, dictated the oath formula, praeivit iusiurandum, and Trajan swore, expressed, pronounced the words clearly by which he devoted his own head and his house to the anger of the gods if he should be false to his oath. And he swore in the presence of the gods, attendentibus diis, in the presence of all those who must swear the same thing, observantibus his quibus idem iurandum est.
The expression recurs a number of times in Livy: Brutus populum iureiurando adegit neminem Romae passuros regnare, he led the people to this oath (II, 1, 9). T. Manlius threatens to kill the tribune if he does not take the oath in the terms which he is going to dictate to him: nisi, in quae ipse concepisset verba, iuraret. The tribune, seized with fear, swears in the terms imposed on him: adiurat, in quae adactus est verba (VII, 5). We now recall the well-known passage in which Hannibal, while still a child, is led to an altar, touches it and takes the oath that as soon as he can he will become the enemy of the Roman people: tactis sacris, iureiurando adactum (XXI 1,4). The verb adigere is standard for saying “to lead someone to the oath,” since the one swearing does nothing but repeat the words dictated to him. Tacitus Hist. 1,37, when speaking of a general who administers an oath to his troops, uses the expression sacramento adigit. Here, then, are the ritual expressions of the ius iurandum: praeire verbis; verbis conceptis; adigere in iusiurandum.
Thus iurare does not designate what we understand by “swearing,” that is, the act of engaging oneself in a solemn way by invoking a god. The oath itself, the “commitment,” is called sacramentum, a term which is preserved in the Romance languages and which yields French serment. At Rome the sacramentum became at an early date the word for the military oath. Here we must therefore distinguish two notions, the sacramentum which is the act of consecrating oneself to the gods, to call on their vengeance if one is false to one’s word; and iurare which is the act of repeating a certain form of words. The taking of an oath requires two persons: the one who praeit verbis, who “precedes with words,” who pronounces the ius, and the one who really iurat, who repeats this formula, which is called ius iurandum ‘the formula to be formulated’, that which must be repeated after the person “qui praeit” has pronounced it, the formula fixing in stereotyped and time-honored terms the text of the engagement.
We thus come back to the literal analysis of iurare. If we start with ius, defined as the formula which lays down the norm, the model, we can define iurare as “to pronounce the ius,” and the ius must be pronounced in verba alicuius qui praeit, ‘in the terms indicated by the one who precedes’. It is the obligatory relation which secures the imperative character of ius iurandum. The expressions “adigere in verba,” “iurare in verba magistri” are a clear indication of the binding nature of the words which the man swearing the oath must reproduce.
Now that we have come to the end of this analysis we find in iurare a confirmation of what the examination of ius itself taught us, namely that ius designates a formula, in the present case the formula which declares what course of conduct the swearer of the oath will take, the rule to which he will conform. But the ius iurandum indicates the nature of the procedure and the solemn character of the declaration, not the text of the oath itself.
By restoring to ius its full value, which is indicated both by its etymological correspondences and the Latin derivation, we reach back beyond “law.” The word derives its value from a concept which is not merely moral but primarily religious: this is the Indo-European notion of conformity to a rule, of conditions which have to be fulfilled before the object (whether thing or person) can be approved, can perform the duties of his office, and be fully effective: yoḥ in Vedic, yaoždā- in Avestan are impregnated with this value. A further result of this investigation has been to establish the connection between ius and sacramentum in Latin vocabulary, the intermediary being the derived verb iurare. Thus the religious and oral origins of law are clearly marked in its fundamental terms.
With the semantic family of iudex we can link a term of an entirely different form, which appears only in Latin, with a correspondent in Umbrian. This is arbiter (Umbr. arputratiarbitratu’), which also designates a judge. Iudex and arbiter are closely associated and often taken for one another, the second being only a specification of the first. He is, therefore, a particular form of judge, the “arbiter.” What concerns us is not so much the etymology as the proper sense of the word. Arbiter has two different senses: (1) the witness, the man who was present on a given occasion, and (2) the “arbiter,” the man who decides between two parties in virtue of some legal power.
How did the “witness” come to be the “judge-arbiter,” “he who decides” between two parties? The dictionary of Ernout-Meillet gives the two senses in succession, without making any attempt to reconcile them. According to the dictionary of Walde-Hofmann, the first sense was “the one who, in his character of disinterested witness, decides between two disputants.” But it is an arbitrary proceeding to agglomerate two distinct meanings in order to achieve a definition.
Here again we are obliged to make a study of the uses of the word. This shows in the first place that by translating arbiter as “witness” we are not giving a complete account of its meaning. We quote a few examples from Plautus which illustrate the oldest and most significant meanings.
Secede huc nunciam si videtur, procul,
ne arbitri dicta nostra arbitrari queant
Come over here, please, a way off, so that arbitri cannot arbitrari our words.
Captivi 219
This already makes it plain that the sense of “witness” does not adequately render the force of the word.
eamus intro, non utibilest hic locus factis tuis
dum memoramus, arbitri ut sint, qui praetereant per vias
Let us go into the house; this is not a suitable place for us to talk about your conduct, the passers-by may be arbitri.
Mercator 1005
mihi quidem iam arbitri vicini sunt, meae quid fiat domi
ita per impluvium intro spectant.
The neighbors are arbitri of everything that goes on in my house: they look through the impluvium.
Miles 158
Sequimini; simul circumspicite ne quis adsit arbiter.
Follow me and at the same time look around to see that there is no arbiter present.
Miles 1137
These passages show clearly the difference between testis and arbiter: the testis is in full view of, and known to, the parties in question; the arbiter sees and hears without being seen himself. The character in Miles 1137 expressly states this: if he does not take precautions, everything will take place in the sight of an arbiter without the parties knowing it. In law the evidence of an arbiter is never invoked as testimony, for it is always the idea of seeing without being seen that the term implies.
The verb arbitrari ‘to be a witness’ has the same implication: a character in the Aulularia of Plautus has been “sent to reconnoiter” (speculatum misit me) to find out what would happen. “I shall go and sit here without anyone suspecting it,” hinc ego et huc et illuc potero quid agant arbitrarier ‘from here, in this direction and in that, I shall be able to arbitrari what they are doing’ (l. 607), that is to say, to see what is going on on both sides without being seen.
How then can we explain the sense “judge” for arbiter? How can the “clandestine witness” evolve into a judge? We must recall that in the most ancient sense of the word the name iudex was given to every authoritative person charged with passing judgment in a disputed case. In principle it was the king, the consul, the holder of all powers. But for practical reasons this power was delegated to a private judge who, according to the nature of the cases, was called iudex or iudex privatus or iudex selectus or arbiter. The last was empowered to decide in all cases which were not foreseen by the law. There was in fact a legis actio for those cases not provided for by the law, and the parties presented the following request “iudicem arbitrumve postulo uti des.” The ancient character of the arbiter in this sense is also attested by the law of the Twelve Tables where we read: praetor arbitres tres dato ‘the praetor shall give three arbitri’. What characterizes the arbiter is the extent of his power, which Festus defines: … pontifex maximus, quod iudex et arbiter habetur rerum divinarum humanarumque and elsewhere: arbiter dicitur iudex quod totius rei habeat arbitrium “the iudex is called arbiter because he has the decision in the whole matter.” In effect, the arbiter makes his decision not according to formulas and the laws but by a personal assessment and in the name of equity. The arbiter is in fact a iudex who acts as an arbiter; he judges by coming between the two parties from outside like someone who has been present at the affair without being seen, who can therefore give judgment on the facts freely and with authority, regardless of all precedent and in the light of the circumstances. This connection with the primary sense of “witness who did not form a third party” makes comprehensible the specialization of the sense of arbiter in legal language.
This was the starting point for the extension of the meaning of the verb arbitrari to the sense of aestimare, to fix in a decisive way the price of something. This particular sense again comes from a specialized use connected with the function of the arbiter: this was the arbitrium litis aestimandae, the indisputable power to assess the price of a disputed object; hence arose the wider sense “to fix the price of something.”
Every time we find technical applications of a term it is advisable to look for the explanation within the sphere to which it belongs, but only after having defined its primary meaning. The same principle and procedure applies on a larger scale when we are trying to determine the proper sense of notions in the vocabulary of institutions.