Frank Duff was born in Dublin in 1889 and began his career in the Irish civil service. His involvement with the Society of St. Vincent de Paul deepened his commitment to serving people living in poverty and strengthened his Catholic faith. In 1921, he founded the Legion of Mary with a small group of people who wished to put their faith into practice through prayer, personal contact, and service to others. The movement spread far beyond Ireland, developing into an international organization active in parishes and communities around the world. Duff devoted the rest of his life to its growth and to promoting the role of ordinary laypeople in the mission of the Church. His legacy is a reminder that faith can be lived through simple, consistent acts of service.