The Immaculate Conception is the doctrine that the Virgin Mary was free of original sin from the moment of her conception.[1] It is one of the four Marian dogmas of the Catholic Church.[2] Debated by medieval theologians, it was not defined as a dogma until 1854,[3] by Pope Pius IX in the papal bull Ineffabilis Deus.[4] While the Immaculate Conception asserts Mary's freedom from original sin, the Council of Trent, held between 1545 and 1563, had previously non-dogmatically affirmed her freedom f