St. Francis Xavier was a Spanish missionary and co-founder of the Society of Jesus, also known as the Jesuits. Born in 1506, he played a crucial role in spreading Christianity in Asia, particularly in India and Japan. His efforts helped establish missions and convert many people to Christianity. Xavier is known for his dedication and commitment to his mission work, often traveling to remote areas to share his faith. He is recognized as one of the greatest missionaries in history and was canonized as a saint by the Catholic Church in 1622. His feast day is celebrated on December 3rd.