The dogma of the divine maternity of Mary was elaborated over time and thus defined the place of Mary in the history of salvation. The first two Marian dogmas (Mary Mother of God and Mary's perpetual virginity) are common to the different Christian faiths: Mary was declared Theotokos ("Mother of God") by the Council of Ephesus (431) and her perpetual virginity was affirmed by the Second Council of Constantinople (553).
The Second Vatican Council did not merely reiterate previously defined truths, instead it re-examined the fundamental mystery of Mary in the broader doctrinal context of the entire mission of the Virgin Mary. In interpreting Mary's consent at the Annunciation, Vatican II emphasized that this consent was given in full freedom and conscience and that it expressed a responsible commitment to the divine invitation to total service to Christ and his saving work (Constitution Lumen Gentium 53.56).
The Council Fathers wanted to present a new and profound synthesis of the Marian doctrine. In two original paragraphs (LG 63-64), Vatican II declared, following St. Ambrose, that Mary is a figure ("typos") of the Church in her virginal motherhood. The Council wished to say that Mary is not the only mother and virgin, but that the Church is also mother and virgin, and that the maternity of Mary is the figure of the maternity of the Church.
In developing this perspective, we can conclude, without fear of betraying the Council, that the saving event of the divine virginal motherhood cannot be considered only as a fact of the past concerning only Mary, but that it is a reality that is renewed at every moment of the fruits of salvation provided by the Church, who lives out her virginal motherhood.
Of course, the generation of Christ through the Virgin Mary and the one through which he continues to be born in the Church are of a different nature and happen in a different way. But what is most important about this aspect of Vatican II's doctrine is that it opens up a new avenue for theological study: divine maternity establishes not only a relationship between Mary and Christ, but also an intimate relationship between Mary and the Church, extending the meaning of divine maternity to the widest area of all salvation history.
Adapted and translated from:
S.MEO. "Madre di Dio", In: Nuovo dizionario di mariologia, a cura di de Fiores, ed. san Paolo 1985, pp. 739-741.
Marian Encyclopedia