Saint Ildefonsus was a 7th-century Spanish bishop of Toledo and a prominent figure in the early Christian church. He is known for his strong defense of the Immaculate Conception of the Virgin Mary and his contributions to the development of Christian doctrine. His writings include several theological works that emphasize the importance of the sacraments and the role of the Church. Ildefonsus is celebrated as a saint in both the Roman Catholic Church and the Eastern Orthodox Church. His feast day is observed on January 23. He is often depicted in art with symbols of his episcopal authority, such as a mitre and crozier, reflecting his leadership and dedication to the faith.