CCC 499 The deepening of faith in the virginal motherhood led the Church to confess Mary’s real and perpetual virginity even in the act of giving birth to the Son of God made man.154 In fact, Christ’s birth "did not diminish his mother’s virginal integrity but sanctified it."155 And so the liturgy of the Church celebrates Mary as Aeiparthenos, the “Ever-virgin”.156
ST. IGNATIUS OF ANTIOCH I give glory to Jesus Christ, the God who has given you wisdom. For I have perceived that you are firmly settled in unwavering faith, being nailed, as it were, to the cross of the Lord Jesus Christ, fully convinced as touching our Lord that he is truly of the race of David according to the flesh, and Son of God by the Divine will and power, truly born of a virgin, . . . .
— St. Ignatius of Antioch Letter To The Smyrneans
ST. IGNATIUS OF ANTIOCH “And from the prince of this world were hidden Mary’s virginity and her child-bearing, in like manner also the death of the Lord.”
— St. Ignatius of Antioch Letter To The Ephesians
The Blessed Virgin’s childbearing would not be “hidden from this world” if She had a mere natural childbirth.
CCC 498b . . . . The meaning of this event is accessible only to faith, which understands in it the “connection of these mysteries with one another” in the totality of Christ’s mysteries, from his Incarnation to his Passover. St. Ignatius of Antioch already bears witness to this connection: “Mary’s virginity and giving birth, and even the Lord’s death escaped the notice of the prince of this world: these three mysteries worthy of proclamation were accomplished in God’s silence.”
Listen to St. Irenaeus back in the late 100’s A.D. almost certainly referring to Mary’s in partu inviolability!
ST IRENAEUS** Immanuel, born] of the Virgin, exhibited the union of the Word of God with His own workmanship, declaring] that the Word should become flesh, and the Son of God the Son of man (the pure One opening purely that pure womb which regenerates men unto God, and which He Himself made pure); and having become this which we also are, (He nevertheless) is the Mighty God, and possesses a generation which cannot be declared.
St. Irenaeus. Against Heresies Book IV, Chapter 33 (180 A.D.)
ST. ATHANASIUS Let those, therefore, who deny that the Son is by nature from the Father and proper to His essence, deny also that He took true human flesh from the Ever-Virgin Mary. In neither case would it have been profitable to us men: if the Word were not by nature true Son of God, or if the flesh which He assumed were not true flesh.
— From St. Athanasius. Discourses Against The Arians (358-362 A.D.)
ST. CYRIL OF ALEXANDRIA** “[T]he Word himself, coming into the Blessed Virgin herself, assumed for himself his own temple from the substance of the Virgin and came forth from her a man in all that could be externally discerned, while interiorly he was true God. Therefore he kept his Mother a virgin even after her childbearing”
— St. Cyril of Alexandria Against Those Who Do Not Wish to
Confess That the Holy Virgin is the Mother of God A.D. 430].
POPE SAINT LEO THE GREAT “His (Christ’s) origin is different, but his (human) nature is the same. Human usage and custom were lacking, but by divine power a Virgin conceived, a Virgin bore, and Virgin she remained”
—Pope St. Leo I (also called Leo the Great)
Died in 461 A.D. (Sermons 22:2A.D. 450]).
POPE SAINT LEO THE GREAT** “She (Mary) brought Him forth without the loss of virginity, even as she conceived him without its loss…(Jesus Christ was) born from the Virgin’s womb because it was a miraculous birth.”
—Pope Leo the Great (Died in 461 A.D.)
St. Augustine (writing approximately in 400 A.D.) wonders: Why all the incredulity?
ST AUGUSTINE** But perhaps it is the unprecedented birth of a body from a virgin that staggers you? But, so far from this being a difficulty, it ought rather to assist you to receive our religion, that a miraculous person was born miraculously.
—St. Augustine City of God Book V, Chapter 29 On the Incarnation of Our Lord Jesus Christ, Which The Platonists In Their Impiety Refuse To Acknowledge
ST. AUGUSTINE “It was not the visible sun, but its invisible Creator who consecrated this day for us, when the Virgin Mother, fertile of womb and integral in her virginity, brought him forth, made visible for us, by whom, when he was invisible, she too was created. A Virgin conceiving, a Virgin bearing, a Virgin pregnant, a Virgin bringing forth,** a Virgin perpetual. Why do you wonder at this, O man?**”
— St. Augustine Sermons 186:1A.D. 411].
St. Augustine tells us about the Antidicomarite heretics. Thye were the heretics who denied the Blessed Virgin Mary’s PERPETUAL Virginity.
ST. AUGUSTINE “Heretics called Antidicomarites are those who contradict the perpetual virginity of Mary and affirm that after Christ was born she was joined as one with her husband”
— St. Augustine Heresies 56A.D. 428]).