Immaculate Conception

The Immaculate Conception is the belief that the Virgin Mary was free of original sin from the moment of her conception. It is one of the four Marian dogmas of the Catholic Church. Debated by medieval theologians, it was not defined as a dogma until 1854, by Pope Pius IX in the papal bull Ineffabilis Deus. While the Immaculate Conception asserts Mary's freedom from original sin, the Council of Trent, held between 1545 and 1563, had previously affirmed her freedom from personal sin.

In the Catholic Church, several locations around the world invoke the patronage of the Immaculate Conception. Catholic diocesan authorities with the expressed and written approval of the Pope in countries including the United States, Brazil, Korea, the Philippines and Spain designate the Blessed Virgin Mary as their principal patroness.

The Solemnity of the Immaculate Conception celebrates the Immaculate Conception of the Blessed Virgin Mary on 8 December, nine months before the feast of the Nativity of Mary on 8 September. It is one of the most important Marian feasts in the liturgical calendar of the Latin Church.

The Congregation of Marian Fathers of the Immaculate Conception of the Most Blessed Virgin Mary (Latin: Congregatio Clericorum Marianorum ab Immaculata Conceptionis Beatissimae Virginis Mariae) is a Catholic male clerical religious congregation founded, 1670, in Poland. It is also known as Marians of the Immaculate Conception. Its members add the post-nominal letters M.I.C. after their names to indicate membership in the Congregation.

Act for the Immaculate Conception of Mary (Catalan: Acte per a la Immaculada Conceptio de Maria) is the name of a dramatic play, in the Catalan language, likely performed in Bethlehem College in Barcelona on May 13, 1662, to celebrate a declaration of Pope Alexander VII in support of the idea of Immaculate Conception.

There are a number of Roman Catholic religious orders or congregations with Immaculate Conception in their name. Several of them are discussed here.