Faustina Kowalska was a Polish Catholic nun and mystic who lived from 1905 to 1938. Born Helena Kowalska, she joined the Congregation of the Sisters of Our Lady of Mercy in 1926. She is best known for her reported mystical experiences and conversations with Jesus Christ, which she documented in her writings. These visions inspired the widespread Catholic devotion to Divine Mercy. Often referred to as the "secretary" of Divine Mercy, her spiritual legacy remains central to modern Catholic practice.