That marriage is instituted for the production of children is a truism. However, the elements of this purpose change depending on the discourse context in which they are discussed. While within the legal discourse we see the focus on the outcome and negotiations around property in marriage, within Christian thought, marriage was broadly developed as a theologically legitimate institution in order to combat the problem of sex. As such, marriage in the post-Imperial West in religious discourse is defined fundamentally by its relationship with the limits of theologically acceptable sexual intercourse.

From the very beginning of Christian writing sexual contact in marriage was a significant problem that needed a solution. The earliest discussions to appear surrounding conjugal sexual relations focused on reassuring potentially wary Christians that marriage was a Christian act, legitimised by Christ and the Bible. This appears in response to the late fourth century Jovinian heresy, which argued that for women the married state and the virginal were equal and promoted a relaxed Christian morality. This prompted a strong backlash from the great Church fathers Jerome and Augustine. Both authored responses to Jovinian with dramatically different modes of attack. Jerome responded in AD 392 with the polemical tract Against Jovinian, which aimed to elevate virginity to celestial heights over marriage, but barely discussed actual marriage at all except in negative terms. Augustine aimed for a more neutral ‘third way’ between the two extremes of Jovinian and Jerome. In AD 401, he responded with his On The Good of Marriage, in which he dismantled Jovinian's heretical teachings while still maintaining that marriage had an important and holy role in Christian life, and that sexual intercourse had a significant place within it. Indeed, Augustine defines the very essence of marriage as consisting of a man and a woman who have agreed to have sexual relations with one another exclusively, as long as they are faithful to that agreement and contraception is not used. Although he maintains throughout that sexual intercourse for pleasure is not ideal, he seems uneasily accepting of the fact that it occurs and is willing to pardon it as long as only one partner is receiving pleasure.