Fulgens corona ("Radiant Crown") is an encyclical by Pope Pius XII, given at St. Peter's, Rome, on 8 September 1953, the Feast of the Nativity of the Blessed Virgin Mary, in the fifteenth year of his Pontificate.

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."

[5] 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, she appeared at the grotto of Massabielle.

[7] "[A]ny honor and veneration which we may give to our Heavenly Mother undoubtedly redounds to the glory of her Divine Son, not only because all graces and all gifts, even the highest, flow from Him as from their primary source".

"[10] He asks for worldwide special prayers, that the sacred rights which are proper to the Church, and which the very exercise of human and civil liberty demands, may be openly and sincerely recognized by all.