Saint Didacus, also known as San Diego de Alcalá, was a Spanish Franciscan friar born in 1400. He is recognized for his deep faith and dedication to serving the poor and sick. Didacus spent much of his life in the Franciscan order, where he became known for his humility and compassion. He was canonized as a saint by Pope Sixtus V in 1588. Saint Didacus is the patron saint of San Diego, California, and his feast day is celebrated on November 13. His life and work continue to inspire many in the Christian faith, emphasizing the importance of charity and service.