A key Mariological claim was settled at the Council of Ephesus in 431 AD.
Many believers of the period began to follow Nestorius in his teaching that Mary ought not to be called “theotokos” (the God-bearer, now loosely translated as Mater Dei, the Mother of God). Nestorius was adamant that Mary ought only to be called Christotokos (the Christ-bearer), but that to call a creature such as Mary the mother of her Creator was nonsensical.
St. Cyril of Alexandria argued against the Nestorian division of Christ’s natures. If she gave birth to Jesus, she had carried within her both his human and divine natures, and could be said to be the God-bearer. The technical term for this theological grammar is the communicatio idiomatum (the communication of idioms). Since Christ is one person with two distinct but hypostatically united natures and two wills in concordance with one another (divine and human), what can be said of his human nature can be said of the whole person. Thus, the divine Word could be said to die on the cross, and the Catechism can state “Christ’s humanity has no other subject than the divine person of the Son of God, who assumed it and made it his own, from his conception. For this reason…Mary truly became the Mother of God by the human conception of the Son of God in her womb” (466).
It’s a fine point, but an important one not only in understanding Mary’s role in salvation history, but also in grasping how as an omnipotent and eternal divine person, Jesus could suffer, weep and share fully in the human experience, including its limitations.
All good theology lives in the both/and between the either/or extremes of excess and defect.
At Jesus’ presentation in the Temple, the prophetic Simeon offers Mary a rather tragic prediction, “a sword shall also pierce your heart.” Simeon could likely have accurately foretold Mary’s role as the Mater Dolorosa, the “Mother of Sorrows.” Watching her innocent son be mocked, scourged, and crucified must have bordered on the unbearable.
Christian art has traditionally depicted Mary’s heart punctured by seven swords, representing her seven sorrows — Simeon’s prophecy, the flight into Egypt, the loss of the child in the Temple, the meeting of Jesus on the path to Calvary, the crucifixion, the deposition and lamentation of Christ’s body (called the pietá when represented alone in Mary’s arms, as most famously by Michelangelo), and the burial. The medieval Lenten hymn Stabat Mater Dolorosa is a powerful testimony to Mary’s trials and her enduring faith in God during them.