Saint Cornelius celebrates the Feast of The Immaculate Conception this December. We celebrate each year on December 8th. This celebration actually honors the conception of the Virgin Mary, despite many thinking it is the conception of her Son, Jesus Christ. 

In 1854, Pope Pius remarked: "The most Blessed Virgin Mary, in the first instant of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the saviour of the human race, was preserved free from all stain of original sin."

We remember this each day, but most notable each year on December 8.