Devotion to the Sacred Heart of Jesus is one of the most popular Catholic devotions. Although it was beloved in previous centuries, Jesus appeared to St. Margaret Mary Alacoque in 1673, showing her a vision of the now-famous image of His Sacred Heart, surrounded by flames. He said to her: “My Heart is so full of love for men that It can no longer contain the flames of Its burning love. I must discover to men the treasures of My Heart and save them from perdition." She was given the special mission to spread devotion to His Sacred Heart throughout the Church. Jesus gave St. Margaret Mary many promises associated with this devotion, and requested that a feast day in honor of His Sacred Heart be instituted on the Friday after the Octave of Corpus Christi. In 1856, the Feast of the Sacred Heart was spread to the Universal Church, and in 1899 Pope Leo XIII solemnly consecrated all mankind to the Sacred Heart of Jesus, calling it “the great act” of his pontificate.