Fulgens corona ("Radiant Crown") is an encyclical by Pope Pius XII, given at St. Peter's Rome, on 8 September 1953, on the Feast of the Nativity of the Blessed Virgin Mary, the fifteenth year of his Pontificate. The encyclical proclaims a Marian year for 1954, to commemorate the centenary of the definition of the dogma of the Immaculate Conception of the Virgin Mary. Fulgens corona is significant as it contained the mariological methodology of Pope Pius XII and his views on limits and challenges of mariology.
In September 1953, Pope Pius XII inaugurated the Roman Catholic Church's First Marian Year, or "Little Holy Year," devoted to the Virgin Mary who had always been the object of his special veneration. He announced the Marian Year in his encyclical letter Fulgens corona. Hundreds of thousands of Romans lined the route of the papal cortege when Pius XII, in one of his rare appearances in the streets of Rome, went to the Basilica of St. Mary Major to open the Marian Year on 8 December 1953, the 99th anniversary of the proclaiming of the dogma of the Immaculate Conception of Mary by Pope Pius IX.
Pius XII begins by recalling his predecessor, Pope Pius IX, who with "apostolic authority defined, pronounced and solemnly sanctioned "that the doctrine, which holds that the Most Blessed Virgin Mary at the first moment of her conception was, by singular grace and privilege of the Omnipotent God, in virtue of the merits of Jesus Christ, Savior of the Human race, preserved from all stains of original sin, is revealed by God, and therefore to be firmly and resolutely believed by all the faithful." (Dogmatic bull Ineffabilis Deus, of Dec. 8, 1854.)"
The Pope stated that the Blessed Virgin Mary, herself seemingly wished to confirm the definition, since less than four years after, in the French town of Lourdes, “the Virgin Mother, youthful and benign in appearance, clothed in a shining white garment, covered with a white mantle and girded with a hanging blue cord, showed herself to a simple and innocent girl at the grotto of Massabielle. And to this same girl, earnestly inquiring the name of her with whose vision she was favored, with eyes raised to heaven and sweetly smiling, she replied: "I am the Immaculate Conception."