“I am the Immaculate Conception.” These are the words our Blessed Mother spoke to young Bernadette Soubirous when she appeared at Lourdes in 1858. On December 8th, we celebrate the Feast of the Immaculate Conception, yet it often seems to leave many people confused. What exactly are we celebrating on this holy day?
Contrary to what many people seem to think, it is not the conception of Jesus. That feast is on March 25th – the Feast of the Annunciation. The Feast of the Immaculate Conception commemorates the conception of Mary in the womb of her mother, St. Anne.
The birthday of Mary has long been celebrated on September 8th. There is evidence that it was celebrated in the Eastern Church on that date as early as the sixth century. It would take a couple more centuries before it was celebrated here in the West.
The information we have on Mary’s birth is not recorded in Scripture. Rather, it comes to us via the Protoevangelium of James written about 150 A.D. It is from this document that we have received the names of Mary’s parents – St. Joachim and St. Anne and the fact that they were childless for many years prior to having Mary.
The Feast of the Immaculate Conception was therefore set on December 8th, nine months prior to Mary’s September birthday. Originally, the Church celebrated this feast as only the Feast of the Conception of Mary. Over the course of the years, as the tradition and understanding of Mary’s conception developed, it became known as the Feast of the Immaculate Conception.
It was officially declared thus on December 8, 1854 when Pope Pius IX declared that the Blessed Virgin Mary “in the first instance of her conception, by a singular privilege and grace granted by God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved exempt from all stain of original sin.”
Original sin was not removed from her soul. Rather, it never existed. In the Eastern Church, this feast is still known as “The Conception by St. Anne.” For more information on the development of this feast, the Catholic Encyclopedia  offers a good treatment.
On a related note, The First Council of Baltimore in 1856 declared Mary, The Immaculate Conception, as the patroness of the United States. The Basilica of the National Shrine of the Immaculate Conception, dedicated to the patroness of the United States and located in Washington, DC, is the largest Roman Catholic church in North America, and one of the ten largest in the world.