ADULTERY (from Lat. *adulterium*, or, according to a probable etymology, *ad alterum torum accensis*). — It is the illicit union of two persons of the opposite sex, at least one of whom is married.
I. HISTORICAL NOTES
Among ancient peoples, the violation of marital fidelity constituted a most grave offense, usually punished by death, but only when committed by the woman. Thus, in Babylon, the Code of Hammurabi decreed that an adulteress caught in the act should be put to death together with her accomplice; and the same penalty was prescribed by Mosaic law (Lev. 20:10; Deut. 22:22), which, in cases where the crime could not otherwise be proven, allowed the husband to subject his wife to the ordeal of the bitter water (Num. 5:11-31).Roman law originally contained no specific provisions regarding adultery (*a.*), its repression being left to the judgment of the domestic tribunal or to the vengeance of the outraged husband. Only toward the end of the Republic, with the *Lex Iulia de adulteriis coercendis* (18 B.C.), did the adultery of a wife—except in the case of a slave woman or a woman of ill repute—come to be regarded as an offense against public morals, ordinarily punishable, following a public accusation, by relegation and confiscation of property; penalties which pagan emperors later aggravated to the extreme penalty of death.
Christian doctrine and morality, reconstructing the institution of marriage upon new ethical and religious foundations and elevating it to the dignity of a sacrament, were to exert a profound influence upon the primitive conception of adultery, not only in the sense of a more lenient repression with a view to possible and effective repentance (John 8:3-11), but also and especially in the sense of an absolute equality of rights and duties between man and woman (1 Cor. 7:4). The adultery of the husband was therefore regarded by the Church as equally sinful as that of the wife, since *eadem a viro quae ab uxore debetur castimonia* (c. 4, C. XXXII, q. 4), and *christiana religio adulterium in utroque sexu pari ratione condemnat* (c. 23, C. XXXII, q. 5). In the first two centuries, it was reckoned among the sins that could not be remitted (at least in certain Churches, and according to canonical discipline, for in the forum of conscience there are no irremissible sins), on a par with apostasy and murder; later, beginning with the edict of Pope Callistus (217-22), absolution was permitted on condition of public penance; and finally, the practice prevailed of imposing a ten-year penance upon a clerical offender and a seven-year penance upon a lay offender (c. 5, D. LXXXII; c. 27, C. XXVII, q. 1).
2. ADULTERY AS A SIN AND AS AN ECCLESIASTICAL CRIME
That adultery constitutes a clear violation of the sixth precept of the Decalogue and represents a mortal sin not only against chastity but also against justice toward the innocent spouse (to which may be added the injury inflicted upon legitimate children by the possible birth of adulterine offspring) is a matter that needs no demonstration.Theologians customarily distinguish between simple adultery, which occurs when only one of the guilty parties is married, and double adultery, which takes place when both are united in marriage. In the first case, it is clear that the unmarried person may be considered formally an adulterer only insofar as he or she is aware of the marital bond by which the other is bound. The tolerance or, worse, the consent of the offended spouse does not remove the character of adultery, since the right to fidelity, acquired at the very moment of the celebration of marriage, is by its nature inalienable and imprescriptible; and this in conformity with the teaching of Innocent XI, who in 1679 expressly condemned the proposition: *"Copia cum coniugata consentiente marito non est adulterium."*
In view of the grave harm that may result to the order of families and, in general, to public morality, adultery is also contemplated by the Code of Canon Law among the crimes against good morals and is punished more or less severely according to the subjective and objective circumstances that accompany II. A layperson who has committed public adultery (that is, such as to cause scandal among the faithful) incurs exclusion from the legitimate ecclesiastical acts until he or she has given signs of sincere repentance (can. 2357, § 2); and the same penalty applies to a minor cleric, for whom, in more serious cases, reduction to the lay state is also envisaged (can. 2358). As for those in sacred orders, can. 2359 distinguishes between simple adultery—generally included under the wording: *"Si... contra sextum decalogi praeceptum deliquerint"*—and a true and proper adulterous relationship: *"Si adulterium... exercuerint."* In the first case, the judge is left to impose fitting penalties (not excluding deprivation of office or benefice) to be determined in each instance according to the gravity of the crime; in the second case, suspension, declaration of infamy, deprivation of any office, benefice, post, or dignity are envisaged, and even—where circumstances so require—the deposition of the guilty party.
A common presupposition to these various criminal figures is the existence of a valid marriage, even if merely ratified. The consummative moment of the crime—which, according to the prevailing doctrine, does not admit of the hypothesis of an attempt—coincides with the sexual act. The psychological element consists in dolus, that is, in the knowledge and will to engage in carnal union with a person bound in marriage or to violate the obligation of fidelity inherent in one’s own married state. Since this is a bilateral crime (which by its nature requires the concurrence of two persons), both guilty parties are subject to the same penalties insofar as they are applicable (cf. can. 2209, § 2 and 2231). Given, finally, the extreme difficulty of obtaining material proof of the crime, ancient canonical practice suggests certain presumptions—natural and legal—of which the judge may still today make useful application.
3. ADULTERY IN CIVIL LEGISLATION
Although there has long been debate (and some still debate) the advisability of criminalizing adultery, all legislations of the civilized world—with the exception of the Danish Penal Code of 1933—repress this crime in varying degrees. The current Italian Penal Code (arts. 559-563), confirming the traditional and not well-justified differentiation in the treatment of the infidelity of men and women, punishes in all cases the adultery of the wife (for which the fact of maintaining an adulterous relationship is envisaged as an aggravating circumstance), while it considers the adultery of the husband a crime only when, by reason of its habitual and notorious nature, it takes on the characteristics of concubinage (q.v.). In both instances the crime is prosecutable only upon complaint by the offended spouse, and the penalty is imprisonment for up to a maximum of two years. Legal separation pronounced for the fault of one spouse excludes the punishability of the other.For adultery as a matrimonial impediment see the entry CRIME, IMPEDIMENT OF; and as a cause of personal separation, see SEPARATION OF SPOUSES.
For adultery among primitive peoples see FAMILY.