Casti Connubii (1930), by Pope Pius XI

By: Katherine Brind'Amour

Casti Connubii

“Casti Connubii,” a papal encyclical given by Pope Pius XI on 31 December 1930, served primarily as a reaffirmation and expansion of the issues discussed in Arcanum, an encyclical written by Pope Leo XIII. It was released to address new threats to marriage and conjugal unity, and indeed is translated “On Christian Marriage” or “On Chastity in Marriage.” The document explores the meaning of Christian marriage and emphasizes its threefold purpose as borrowed from St. Augustine: to produce offspring, to grow in conjugal faith, and to show benefit from the sacrament. It begins by exploring the nature of marriage, followed by a discussion of its advantages for individuals and societies, erroneous but common beliefs about marriage, threats to pure marriage, and finally how to address them. Included in the threats to pure marriage is that of the growing popularity of contraception and abortive procedures, at which point Pope Pius XI elaborates on the Church’s statement that life begins at conception. Pope Pius XI’s account of the true purpose of Christian marriage places significant weight on the proper use of sexuality in marriage, in keeping with the Roman Catholic tradition. The stated primary function of this aspect of marriage is procreation for the generation and education of children. In addition to bringing a couple closer together, the exclusivity of this act is considered essential to marital happiness and adultery is strongly condemned. With respect to growing in conjugal faith, “Casti Connubii” emphasizes the importance of mutual respect and dignity for the ultimate companionship between partners and an increased closeness to God. Finally, the sacrament of matrimony is reiterated as a bond that binds two people by the power God, and as such cannot be destroyed by the manmade division of divorce. Approximately halfway through the document, Pope Pius XI turns his attention to some of the modern obstacles that pose a threat to the Catholic perspective on holy matrimony. The principle offenders are identified as abortion and contraception, and while the document heavily references St. Augustine, the Bible, and Pope Leo XII’s writings, Pius XI inserts additional explanations and guidance to specifically address new challenges. “Casti Connubii” regards all abortion as the unlawful taking of an innocent life, regardless of the level of development of the fetus or the family’s circumstances. Similarly, procedures performed with the intent of sterilizing someone or preventing future pregnancies are rejected as against nature. This document also contains a very strong condemnation of eugenic sterilization, which was commonly performed on prisoners and disabled citizens at the time with the intention of preventing them from procreating. Contraception is regarded as the same grave assault on marital purity as it was by St. Augustine, and any attempts to unnaturally limit the number of children a couple has is reaffirmed as sinful and dangerous to a Christian relationship. Pope Pius XI also used this document to voice the Church’s resistance to new social values taking hold during this time period. With divorce rates increasing and the popularity of alternative lifestyles, “Casti Connubii” warned that the new attitudes would jeopardize the benefits and purposes of marriage. While this document is very vocal about the challenges facing Christians seeking a holy union, it is also vocal about solutions. In addition to suggesting strict adherence to Church doctrines on the matter of marriage, Pope Pius XI recommended that governments opt to assist struggling families with the necessary money for raising families as opposed to funding abortion providers or enacting forced sterilization policies. “Casti Connubii” covers a wide variety of topics concerning Christian marriage and reproductive rights, and in doing so gives an interesting window into the Church’s perception of the social and religious situation surrounding marriage and procreation at the time. This document remains an important part of the Catholic Church’s doctrines, and influenced Pope Paul VI’s Declaration on Abortion. Overall, this document provides a good example of the Catholic approach to marriage, dissolution, contraception, sterilization, and abortion.


  1. Handren, Walter J. No Longer Two: A Commentary on the Encyclical ‘Casti Connubii’ of Pius XI. Westminster: Newman Press, 1955.
  2. Pius XI. “Casti Connubii.” The Holy See. (Accessed June 25, 2007).


How to cite

Brind'Amour, Katherine, "Casti Connubii (1930), by Pope Pius XI". Embryo Project Encyclopedia ( ). ISSN: 1940-5030


Arizona State University. School of Life Sciences. Center for Biology and Society. Embryo Project Encyclopedia.

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Monday, September 11, 2023 - 10:58

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