Incest (Lat. in, not; castus, chaste), the crime of sexual commerce with a person within the degrees forbidden by the (Levitical) law (see Trier, De legibus Mo; saicis de incestu, Frcft. a. Oder, 1726). SEE AFFINITY CONSANGUINITY. "An instinct almost innate and universal," says Gibbon (Decline and Fall of the Roman Empire, 4, 351), "appears to prohibit the incestuous commerce of parents and children in the infinite series of ascending and descending generations. Concerning the oblique and collateral branches, nature is indifferent, reason mute, and custom various and arbitrary. In Egypt, the marriage of brothers and sisters was admitted without scruple or exception; a Spartan might espouse the daughter of his father, an Athenian that of his mother; and the nuptials of an uncle with his niece were applauded at Athens as a happy union of the dearest relations. The profane lawgivers of Rome were never tempted by interest or superstition to multiply the forbidden degrees; but they inflexibly condemned the marriage of sisters and brothers, hesitated whether first cousins should be touched by the same interdict, revered the parental character of aunts and uncles, and treated affinity and adoption as a just imitation of the ties of blood. According to the proud maxims of the republic, a legal marriage could only be contracted by free citizens; an honorable, at least an ingenuous birth, was required for the spouse of a senator; but the blood of kings could never mingle in legitimate nuptials with the blood of a Roman; and the name of 'stranger' degraded Cleopatra and Berenice to live the concubines of Mark Antony and Titus." Vortigern, king of South Britain, equaled, or, rather, excelled the Egyptians and Persians in wickedness by marrying his own daughter. The queen of Portugal was married to her uncle and the prince of Brazil, the son of that incestuous marriage, wedded his aunt. But they had dispensations for these unnatural marriages from his holiness. "In order," says Paley, "to preserve chastity in families, and between persons of different sexes brought up and living together in a state of unreserved intimacy, it is necessary, by every method possible, to inculcate an abhorrence of incestuous conjunctions; which abhorrence can only be upheld by the absolute reprobation of all commerce of the sexes between near relations. Upon this principle the marriage, as well as other cohabitation of brothers and sisters of lineal kindred, and of all who usually live in the same family, may be said to be forbidden by the law of nature. Restrictions which extend to remoter degrees of kindred than what this reason makes it necessary to prohibit from intermarriage are founded in the authority of the positive law which ordains them, and can only be justified by their tendency to diffuse wealth, to connect families, or to promote some political advantage." The Roman law calls incestuous connection Incestus juris gentiun, while it designates as Incestus juris civilis the intercourse between other members of the families which it considers within the forbidden degrees. The principal law against incest, however, is the Lex Julia de adulteriis coercendis of Augustus. Children born of incest (liberi incestuosi) are by it bastardized. The canon law extended the forbidden degrees very far thus giving a more extended signification to the appellation of incest. By it a distinction was made between the Incestusjuris diviini, relating to such degrees of relationship as were already condemned by the Mosaic law, and the Incestus juris hunmani, relating only to such degrees within which marriage is forbidden by ecclesiastical laws. But as in the latter case dispensations can, in the Romish Church, always be obtained, this form of incest is merely considered an offense against the laws of the Church. The penal statute of Charles V concerning incest is based on the Roman law, but includes also cohabitation with a daughter-in-law, a stepdaughter, and a mother-in-law. Consequently incest, properly so called, can only take place between ascendants and descendants, brothers and sisters, parents-in- law and children-in-law, stepparents and step-children. Prosecution for incest, however, is legal only in cases where persons have had sexual intercourse without marriage; it is inapplicable where marriage has been contracted in good faith, and only afterwards the contractors become aware of their connection being incestuous. Modern law, which in the main is based on the Levitical, and from which the rule of the Roman law differs very little, prohibits marriage between relations within three degrees of kindred; computing the generations not from, but through the common ancestor, and accounting affinity the same as consanguinity. The issue, however, of such marriages are not bastardized unless the parents be divorced during their lifetime. Penalties are enacted for incest and unchastity varying from simple imprisonment to hard labor for a term of five or six years. Sexual intercourse between parties in different degrees of the collateral lines is in many cases considered only as punishable by the police regulations. The ascendants are generally punished more severely than the descendants. The modern Jews permit the marriage of cousins, and even of the uncle by a niece. See Pierer, Universal Lexikon, 8, 841; Paley, Moral Philosophy, 1, 316 sq.; Buck, Theological Dictionary, s.v.