During the Pontificate of Leo XIII, a letter reached the Vatican from Oporto, Portugal, written by the Superior of the Good Shepherd Nuns, known in the Community as Sister Mary of the Divine Heart, who claimed that Christ, in a supernatural vision, had instructed her to inform His Vicar that he should consecrate the whole world to His Sacred Heart. Needless to say, careful inquiries were made and mature consideration given to this matter. Cardinal Jacobini communicated the result of his investigation to the Roman Pontiff, stating that the writer of the epistle was regarded as a saint by all who came in contact with her, and that there was no reason to entertain a misgiving about her claim to a revelation. On the strength of this declaration Leo XIII in 1899 raised the Feast of the Sacred Heart to the dignity of a double of the first class, and, at the same time, in order to accede to so unexampled an entreaty, composed and prescribed the formula by means of which the whole world was to be consecrated to the Sacred Heart. Thus originated the concession which ever after he used to style the " Great Act" of his Pontificate.
The extensive influence of this devotion is evidenced in the fact that, up to the present, at least sixteen different religious Communities have been established by various founders who have selected the name of the Sacred Heart to serve as a special incentive and inspiration for their followers. There are, moreover, eleven distinct devotions calculated to promote the honor and external glory of this Object of Love in some particular way.
From the foregoing survey it is manifest that a special Divine Providence was co-operating with the Church in order that Devotion to the Sacred Heart should attain the high distinction and popularity of which it is most deserving. At the present time the devotion is productive of unlimited good; it is widely diffused, and occasions the salvation of many souls. This fact was appreciated by the great Pontiff when, in his Encyclical, he used this striking and appropriate comparison: " In the past, a cross appeared to Constantine, a pledge of faith and victory. And, behold, to-day a new sign offered to our eyes, a token most auspicious and divine. Such is the Sacred Heart shining brilliantly amid flames. It is there we are to place all our hopes, it is from that Source we are to expect the salvation of mankind."
