<P> The Immaculate Conception, according to the teaching of the Catholic Church, is the conception of the Blessed Virgin Mary free from original sin by virtue of the merits of her son Jesus Christ . The Catholic Church teaches that God acted upon Mary in the first moment of her conception keeping her "immaculate". </P> <P> The Immaculate Conception is commonly confused with the Virgin Birth of Jesus . Jesus' birth is covered by the Doctrine of Incarnation, while the Immaculate Conception deals with the conception of Mary, not that of her son . </P> <P> Although the belief that Mary was sinless, or conceived without original sin, has been widely held since Late Antiquity, the doctrine was not dogmatically defined until 1854, by Pope Pius IX in his papal bull Ineffabilis Deus . The Catholic Church celebrates the Feast of the Immaculate Conception on December 8; in many Catholic countries, it is a holy day of obligation or patronal feast, and in some a national public holiday . </P> <P> The defined dogma of the Immaculate Conception regards original sin only, saying that Mary was preserved from any stain (in Latin, macula or labes, the second of these two synonymous words being the one used in the formal definition). The proclaimed Roman Catholic dogma states, "that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved free from all stain of original sin ." Therefore, being always free from original sin, the doctrine teaches that from her conception Mary received the sanctifying grace that would normally come with baptism after birth . </P>

When was the immaculate conception made a dogma