All About Mary
Immaculate Conception: Ineffabilis Deus
The Immaculate Conception
– Denis Vincent Wiseman, O.P.
On December 8, 1854, Pope Pius IX, in the bull Ineffablis Deus, proclaimed: We declare, pronounce and define that the doctrine which holds that the Blessed Virgin Mary, at the first instant of her conception, by a singular privilege and grace of the Omnipotent God, in virtue of the merits of Jesus Christ, the Savior of mankind, was preserved immaculate from all stain of original sin, has been revealed by God, and therefore should firmly and constantly be believed by all the faithful.1