Question: In what year did Pope Pius IX make his Ex Cathedra proclamation of the Immaculate Conception of Mary?
Sentence: Roman Catholics believe in the Immaculate Conception of Mary, as proclaimed Ex Cathedra by Pope Pius IX in 1854, namely that she was filled with grace from the very moment of her conception in her mother's womb and preserved from the stain of original sin.
Answer in sentence: yes