Saint Alphonsus Liguori was an Italian bishop and theologian born on September 27, 1696. He founded the Congregation of the Most Holy Redeemer, also known as the Redemptorists, to focus on preaching and serving the poor. He is known for his deep spirituality and writings on moral theology, emphasizing God's mercy and love. Liguori was canonized as a saint by Pope Gregory XVI in 1839 and declared a Doctor of the Church in 1871. His feast day is celebrated on August 1. He is the patron saint of confessors and moral theologians, and his works continue to influence Catholic thought today.