The Immaculate Conception is a dogma of the Catholic Church maintaining that from the moment when she was conceived the Blessed Virgin Mary was kept free of original sin and was filled with the sanctifying grace normally conferred during baptism. It is one of the four dogmas in Roman Catholic Mariology. Mary is often called the Immaculata (the Immaculate One), particularly in artistic and cultural contexts.
The Immaculate Conception should not be confused with the perpetual virginity of Mary or the virgin birth of Jesus; it refers to the conception of Mary by her mother, Saint Anne. Although the belief was widely held since at least Late Antiquity, the doctrine was not formally proclaimed until December 8, 1854, by Pope Pius IX in his papal bull Ineffabilis Deus. It is not formal doctrine except in the Roman Catholic Church. The Feast of the Immaculate Conception is observed on December 8 in many Catholic countries as a holy day of obligation or patronal feast, and in some as a national public holiday.
Bernadette asked the woman a fourth time, "Who are you?"
The Lady smiled and answered:
"I am the Immaculate Conception."
O God, who by the Immaculate Conception of the Blessed Virgin Mary,
didst prepare a worthy dwelling place for thy Son, we beseech thee that,
as by the foreseen death of this, thy Son, thou didst preserve her from all stain,
so too thou wouldst permit us, purified through her intercession, to come unto thee.
Through the same Lord Jesus Christ, thy Son, who livest and reignest
with thee in the unity of the Holy Ghost, God, world without end.