Archive Civic Polity Corpus Iuris Civilis E.J. Hutchinson

Latin Terms for “Law”: Fas, Ius, and Lex

Fas, Ius, and Lex: Vergilian Prelude

fas mihi Graiorum sacrata resolvere iura,
fas odisse viros atque omnia ferre sub auras,
si qua tegunt; teneor patriae nec legibus ullis.
(Aeneid 2.157–59; emphases mine)

This is justice, I am justified
in dropping all allegiance to the Greeks–
as I had cause to hate them; I may bring
into the open what they would keep dark.
No laws of my own country bind me now.
(tr. R. Fitzgerald)

In Book 2 of Vergil’s Aeneid, the Greek pseudo-traitor Sinon, who convinces the Trojans to bring within the city walls the wooden horse pregnant with Greek killers, speaks as though he hates the Greeks, because they, spurred on by the archetypal trickster Ulysses, had betrayed him and were about to sacrifice him in order to secure winds favorable to their passage home – an eventuality only narrowly avoided by his improbable escape. (I can’t resist pointing out here that the first Christian epic poet, Juvencus, in part models the captive Christ, being taken before Pilate, on Vergil’s Sinon: just as Sinon is bound post terga revinctum, “bound behind his back,” (Aeneid 2.57), so is Christ post terga revinctum (Evangliorum Libri Quattuor 4.588) – where Sinon feigns that he was nearly a victim of sacrifice for treacherous ends, Christ really becomes one for righteous and merciful ends). To these scoundrels Sinon no longer belongs, and by their laws he is no longer bound.

In justifying his revelation of Greek secrets to the Trojans, normally forbidden by laws of various kinds, Sinon speaks very much like a Roman, and in the passage quoted above uses the three most important terms having to do with law (obscured somewhat in Fitzgerald’s translation): fas, ius, and lex. This is a deliberate move meant to carry persuasive weight with the Trojans, to increase his integrity in their eyes, and thus to lead the Trojans to adopt him as one of their own (which they do: as Priam says in 2.149, noster eris, “you will be ours”). These terms each have a distinctive sense, and so we would do well to consider the differences between them, especially because they will prove important for future treatments of topics in Roman law. I shall begin from the passage in Vergil and move outward from there.

Nicholas Horsfall, in his recent commentary on Aeneid 2 (Brill, 2008), notes that what is fas has to do with divine law (157): something that is fas is “allowable under divine law” (Horsfall is here quoting R. G. Austin on Aeneid 6.266, who in turn is drawing on Kurt Latte, Römische Religionsgeschichte; on Warde Fowler, Religious Experience of the Roman People; and on Oskar Hey, Archiv für lateinische Lexicographie und Grammatik, vol. 13). R. G. Austin, in his commentary (Oxford, 1964) notes something similar: Fas est implies not what is compulsory but what is allowable without transgressing the law of heaven” (81–82). “Sinon,” Austin writes, “uses every effort to make it appear morally right for him to betray his country; he has no ties now, no religio holds him back; what would normally be the worst kind of nefas is now fas.”

Forgive me for a momentary digression, but there is some interesting etymology in play with this term. Oskar Hey, in the work referred to above (212–14), argues for a link (though the Oxford Latin Dictionary says the etymology of fas is doubtful) between fas and fatum, “divine law” and “fate,” tracing both of them back to the Latin verb for, fari, “to speak.” Fas, then, refers to an actio fandi, an act of speaking, while fatum is a participial form referring to what has been spoken. The semantic range of these two words would, then, have been originally distinct: fatum, fate, is jenseits von Gut und Böse, “beyond good and evil” – it is “what is necessary” (necesse est); fas, on the other hand, is “what is permitted” (licet), and thus is fundamentally moral. Despite this original distinction between the two terms, however, they do come at times to be used interchangeably, as Hey shows.

Back to Vergil. For iura here, Horsfall raises two possibilities (158): they “are either the simple ‘rules and regulations’ observed by the Greek army, not distinct from the ‘laws,’ ” or, “much better,” they are ” ‘shorthand’ for ‘oaths’ (plur. iura iuranda uncommon).” That the latter is better is indicated by the modifier sacrata, for oaths regularly are viewed in antiquity as sacred affairs; Horsfall points out that the sacramentum, the Roman military oath, may be in the background as well. But one shouldn’t push the precise nature of the oath too far: “…Sinon does not care a scrap about oaths and witnesses and is exercised solely by the convincing, reliable impression he must make upon the Trojans, so we should not try too hard to work out exactly why and how Sinon is to be thought of as bound (sc. by oath) not to reveal the Greeks’ secrets” (158).

Finally, Sinon claims that he is free from Greek leges (teneor patriae nec legibus ullis). Austin points out that this is “a formal renunciation of the binding force of Greek jurisdiction, and a restatement of Graiorum sacrata resolvere iura” (82). But the two are not simply synonymous (no pun intended): “The whole passage has a very Roman ring: the juxtaposition of fas, iura (the body of law in general), legibus (the written enactments), is not fortuitous.”

Broader Considerations: Semantics and Etymology

This last distinction – regarding the difference between iura as a body of law and leges as particular written laws – widens our scope for investigation, for which I shall refer to Henry Nettleship‘s Contributions to Latin Lexicography (Oxford, 1889), also used by Austin. Nettleship notes (497–500) seven different broad categories of meaning for ius (and here I reproduce in most instances what Nettleship says, word for word):

    1. a law-court;
    2. a bond or tie: that which binds or holds;
    3. power, authority;
    4. right to do a thing – “a power, the exercise of which is generally approved, to do a thing”; the plural iura can be used for “rights”;
    5. law, or a system of law: “Law, either in the most general sense of the word or in the sense of a particular system of law governing a particular people”; the word in this sense is often found in phrases such as ius fasque, “human and divine law”; “Ius in this case is the body or contents of a number of special enactments, law in general, as distinguished from lex [for more on which, see below], a special written enactment (or, properly, contract between the magistrates and the people);
    6. what is right and fair; and, thus, the opposite of this is iniuria, whence our word “injury,” “what is unfair”;
    7. in the plural, either rights, or rules of law, ordinances, decisions, and so authority. The etymology of the term is not entirely clear; Lewis & Short connects it with a Sanskrit term meaning “to join,” as well as Greek ζεύγνυμι, “to yoke, bind, join” and Latin iungo, “to join.”

If this is right, the word potentially emerges from a  background similar to that of lex (see below). The more recent Oxford Latin Dictionary, on the other hand, connects ius with a Sanskrit term meaning “health” and an Avestan one meaning “purifies.” On to lex, then. A lex (Nettleship, 515–17), in contrast to ius, is

[a] definite agreement, statement, or form of words, according to which a business transaction or a process at law is carried out, or a commission executed. Ius is either a law, or rule, or power, or right existing prior to a lex; or a decision, or power, or right, granted in accordance with a lex; or a provision or ordinance included in a lex. The two main meanings of lex are (1) a stated or written condition or understanding proposed and accepted; (2) a written law.

The Romans usually named their laws after the person who proposed them (e.g., lex Tullia, a law proposed by Tullius) and indicated the subject of the law adjectivally (e.g., lex annonaria, a law having to do with grain). The meaning of lex was also metaphorically extended to concerns other than those of the state, “in the sense of a law or principle on which anything is done.” Etymologically, Nettleship reviews the possible derivations: from leg-, to read; lagh-, to lay or set; lig-, to bind. He favors the last as most likely (it is thus possibly related to religio, “religion”). It may, then, “originally mean a bond, a tie, a restraint.”


To conclude: of the three terms, fas has to do with divine law, and seems to be connected to the act of speaking – what the gods say sets parameters for the way that men can behave. The other two terms, referring to human types of law, take their place underneath what is fas, and bind men in various ways in an ordered society, with ius sitting behind and underwriting the particular leges enacted.

By E.J. Hutchinson

E.J. Hutchinson is Assistant Professor of Classics at Hillsdale College.

One reply on “Latin Terms for “Law”: Fas, Ius, and Lex”

[…] That action, that “granting,” has, in its turn, an object: ius–what is right, what is obligatory, what is due. Ius, then, encompasses both rights and duties. A person has a right to receive his ius, his due, and the other is obligated to give it to him.  There is an etymological connection in Latin that is absent in English: the peculiar quality of the concept iustitia consists in a rendering of ius (for a discussion of the range of this term, see here). […]

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