The Immaculate Conception is a dogma of the Catholic Church maintaining that the Blessed Virgin Mary was kept free of original sin from her moment of conception and was filled with the sanctifying grace normally conferred during baptism.^[2][3] 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.^[4]

The Immaculate Conception should not be confused with the 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.^[5] The Feast of the Immaculate Conception is observed on December 8 in many countries as a Holy Day of Obligation and in some places as a national or public holiday.