Adversus Helvidium

On the Perpetual Virginity of Blessed Mary Against Helvidius (De perpetua virginitate beatae Mariae adversus Helvidium) is an apologetic work of Saint Jerome which refutes Helvidius’ stance on Mary’s virginity. (c. AD 342/7–420). Helvidius took the view that although Mary was a virgin at the time she conceived Jesus, she and Joseph had sexual relations subsequently — hence the brothers and sisters of Jesus mentioned in the Gospels. Jerome, in contrast, argued vigorously for the perpetual virginity of Mary, whom he deemed exemplary for women making (or contemplating) vows of virginity. In Jerome's interpretation, the brothers and sisters of Jesus became cousins, while Joseph himself (in correction of earlier traditions) was transformed into a lifelong celibate to serve as a model for Christian men. For Jerome, Joseph was Mary's guardian, not her husband; the relation was not a marriage, which for Jerome implied sex.

Saint Jerome maintains against Helvidius three propositions:
 * That Joseph was only putatively, not really, the husband of Mary.
 * That the "brothers" of the Lord were his cousins, not his own brothers.
 * That virginity is better than the married state.