St Faustina Kowalska's vision of the King of Divine Mercy, Płock, 1931

Płock, 1930. A young lay sister arrived at the convent of the Congregation of the Sisters of Our Lady of Mercy on Stary Rynek, high above the Vistula. Her name was Sr. Maria Faustina Kowalska. She was 25. She worked in the convent bakery and bread shop with Sr. Krystyna Korzeniowska. According to one account, she had been sent there to rest after the first signs of an illness, later thought to be tuberculosis.

Sunday, 22 February 1931. The first Sunday of Lent. In the evening, Faustina was in her cell in the convent annex.

She later wrote: "I saw the Lord Jesus clothed in a white garment." One hand was raised in blessing. The other touched the garment at the breast. From beneath it, slightly drawn aside, came "two large rays, one red, the other pale."

At first, nothing was said. "In silence I gazed intently at the Lord; my soul was overwhelmed with fear, but also with great joy." Then, after a while, she heard the words: "Paint an image according to the pattern you see, with the signature: Jesus, I trust in You." The image was to be venerated first in her chapel, and then throughout the world. A promise followed. "I promise that the soul that will venerate this image will not perish."

She told none of the other nuns, only her superior and her confessor. The confessor took the request to mean painting God's image in her soul. The superior did not take it seriously, answering "Well, paint the image then, Sister!" and asking for a sign. Faustina asked her fellow sisters for help with the painting and got none. In November 1932 she left for Warsaw and never came back.

Vilnius, 1933. Fr. Michał Sopoćko became her confessor. "I ignored what she had told me and I put her to a test," he later recalled. He insisted on a psychiatric evaluation by Dr Helena Maciejewska, which found her of sound mind. Then he asked her to keep a diary. Her account of that night in Płock was written there, at least three years after the event.

In 1934 Sopoćko brought in the painter Eugeniusz Kazimirowski. For about six months Faustina visited the studio at least once a week. Sopoćko himself posed for the figure. Neither of them liked the result. She wept: "who will paint You as beautiful as You are?"

Rome was not convinced. On 6 March 1959 the Holy Office prohibited images and writings promoting the devotion "in the forms proposed by Sister Faustina". No reasons were published. Explanations offered later include a faulty translation of the diary, serious theological reservations, and concern that the red and pale rays looked like the Polish flag. Karol Wojtyła, as Archbishop of Kraków, opened her cause in 1965. On 15 April 1978 the Congregation for the Doctrine of the Faith withdrew the ban.

No source accuses anyone of fraud, and no published sceptical study deals with this vision. The record rests on a single witness, writing years later. Readers have noted that its imagery resembles earlier devotional art, such as the Sacred Heart.

Faustina was beatified on 18 April 1993 and canonised on 30 April 2000. That same day, Divine Mercy Sunday became a feast of the whole Church, and the Płock chapel became a diocesan shrine. The annex that held her cell is gone. Since 2019 a 26 m tower with a steel cross has stood on the spot, lit blue and red after the two rays. A plaque tells visitors: "In this house on the 22nd February 1931 Sister Faustina experienced her first revelation of the Image of Merciful Jesus."