Who declared the dogma of the Immaculate Conception?

Answer 1

In 1858, in an apparition the Church has approved as true and worthy of the belief and devotion of Catholics, the Blessed Virgin appeared to St. Bernadette Soubirou and called herself, "The Immaculate Conception", thereby identifying herself by the doctrine of the same name that had been declared in 1854.

Answer 2

A:

Pope Pius IX proclaimed the doctrine of the Immaculate Conception in 1854. Strictly speaking, this was not an infallible doctrine, as the First Vatican Council had not yet approved the doctrine of papal infallibility. However, in 1870 the Vatican Council voted almost unanimously for the doctrine of papal infallibility, with only 2 opposed. One of Pius' opponents at the Council was subsequently excommunicated.

Catholic Answer:

The doctrine of the Immaculate Conception was defined and declared by Pope Pius IX on December 8, 1854.