Alphonsus Liguori (1696-1787) was an Italian Catholic bishop, spiritual writer, and founder of the Congregation of the Most Holy Redeemer, known as the Redemptorists. He was born into nobility and was a successful lawyer before becoming a priest. Liguori is renowned for his moral theology writings and devotion to the Virgin Mary. He was a prolific author, composing numerous books on spirituality, prayer, and devotion to Jesus Christ. Canonized as a saint in 1839, he is recognized as a Doctor of the Church for his contributions to Catholic theology and spirituality.