The term ever-virgin was used officially at the Fifth Ecumenical Council in Constantinople in A.D. 553. This term is connected to the belief that the Virgin Mary was a virgin both before she gave birth to Christ and afterward. References to Mary's ever-virginity can be found, for example, in the writings of Peter of Alexandria, Epiphanius, Athanasius, Didymus the Blind, Jerome, Cyril of Alexandria, Leo, Sophronius of Jerusalem, John of Damascus, John Cassian, Ephrem of Syria, and the Second Council of Constantinople in A.D. 553, which said, “If anyone shall not confess that the Word of God has two nativities, the one from the Father, from all eternity, without time and without body; the other in these last days, coming down from heaven and being made flesh of the holy and glorious Mary, Mother of God and ever-virgin, and born of her: let him be anathema.”

The word anathema means “cut off from the community.” It is used by Saint Paul in 1 Corinthians 16:22, “If anyone does not love the Lord Jesus Christ, let him be anathema.” It becomes a kind of technical term used as a way to denounce a person's immoral behavior or false teachings.

These terms — theotokos, panagia, and aeiparthenos (evervirgin) — were continually used in traditional Christian liturgies, especially after these disputes, as a way to seal the declarations in people's hearts and to bring clarity to their prayers. There is an ancient saying that “the rule of prayer is the rule of belief” (lex orandi, lex credendi) — in other words, theology and prayer reinforce each other, so they shouldn't be separated.