Maria Faustina Kowalska, born Helenka Kowalska (August 25, 1905, near Lodz, Poland – Died October 5, 1938, Kraków, Poland) was a Polish nun, mystic and visionary. She is venerated in the Vatican II church as a "saint", and is known as the Apostle of Divine Mercy. Throughout her life, she reported a number of visions of Jesus and conversations with him, which she wrote about in her diary, later published as the book Diary: Divine Mercy in My Soul.
A local devotion under this title of Divine Mercy, which is associated with one Sr. Faustina and a chaplet of the Divine Mercy, was used in Vilnius, Poland, in 1936 and from there spread rapidly, especially after World War II in the United States.
Most of her "diary" was concocted by her sisters after her death. Because its orthodoxy was in doubt and because of the incongruities of the dairy (different handwriting, different use of terms), the devotion and image was suppressed, and the book of her diary was placed on the "Index of Forbidden Books" by Vatican II initiator John XXIII in 1959.
In early 1978, a Polish "cardinal" petitioned the Vatican to remove the suppression of the devotion, which was being practiced without sanction in his diocese, and the Vatican replied in the negative, confirming the suppression. Later in 1978 a Polish "pope" was elected, and the now, twice suppressed devotion, was now entered onto the Novus Ordo liturgical calendar on the Octave of Easter.