The Perpetual Virginity of Blessed Mary is an apologetic work of St. Jerome. It is an answer to Helvidius.
Helvidius was the author of a work written about the year 383 against the belief in the perpetual virginity of Mary (the mother of Jesus).
St. Jerome maintains against Helvidius three propositions:
1st. That Joseph was only putatively, not really, the husband of Mary. 2d. That the "brothers" of the Lord were his cousins, not his own brothers. 3d. That virginity is better than the married state.References
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