The Immaculate Conception is a dogma of the Catholic Church which states that Mary, mother of Jesus has been free of original sin from the moment of her conception. It proved controversial in the Middle Ages, but was revived in the 19th century and was adopted as Church dogma when Pope Pius IX promulgated Ineffabilis Deus in 1854. This followed Ubi primum, a 1849 encyclical wherein Pius had asked the bishops for their opinions on the matter, resulting in overwhelming support from the Church's hierarchy.
