At what date did the Catholic Church adopt the idea of the Immaculate Conception by Jesus Mother?
I am afraid you are confusing two different doctrines. The Immaculate Conception is a term referring to the conception of Mary herself by her parents, Joachim and Anne. When Mary herself was conceived, her soul was preserved immaculate, or free from inherited original sin. But when Mary herself conceived Jesus, it was under the influence of the Holy Ghost, and not through any relations with man. This could be called the miraculous conception of the child Jesus. Usually it is referred to as the Virgin Birth, since it implies that Mary remained a virgin even though she gave birth to Jesus. Both the docrtine that Jesus was born of a virgin, and that the virgin was herself immaculate from the very moment of her own conception are taught in the Gospels. But the latter doctrine is not so clearly recorded as the former. That Jesus was born of a virgin Mother has been explicitly taught by the Catholic Church from the very beginning. So in the Apostles’ Creed itself we say, “born of the Virgin
