Saint Maria Faustina Kowalska (born Helena Kowalska; August 25, 1905 – October 5, 1938) was a Polish Catholic nun and mystic, widely known as the “Apostle” or “Secretary” of Divine Mercy.
She was born in the village of Głogowiec (near Łódź), Poland, the third of ten children in a poor but devout peasant farming family. She received only about three years of formal schooling and worked as a housekeeper from her mid-teens to support herself and her family. From childhood she felt a religious vocation, which intensified after a vision of the suffering Jesus in 1924.
In 1925 she entered the Congregation of the Sisters of Our Lady of Mercy in Warsaw, taking the religious name Sister Maria Faustina of the Blessed Sacrament. She professed perpetual vows in 1933 and served in various convents (notably in Kraków, Vilnius, and Płock) primarily as a cook, gardener, and doorkeeper.
She reported numerous visions and conversations with Jesus.
Despite fragile health (she suffered from tuberculosis of the lungs and digestive system), she accepted her sufferings as a sacrifice for sinners. She died in Kraków at age 33 and is buried at the Shrine (Basilica) of Divine Mercy in Łagiewniki, Kraków.
Pope John Paul II beatified her on April 18, 1993, and canonized her on April 30, 2000 (Divine Mercy Sunday), establishing the Feast of Divine Mercy for the universal Church at the same time.
Her optional memorial is observed on October 5. The Divine Mercy devotion she helped spread has become one of the most popular in the modern Catholic Church.