St. Cyriacus is a Christian martyr celebrated in various traditions, particularly in the Roman Catholic Church. He is believed to have lived during the 3rd century and is often associated with the early persecution of Christians under the Roman Empire. His feast day is observed on August 8. According to tradition, St. Cyriacus was a priest who was arrested for his faith and ultimately executed. He is often depicted in art holding a cross or a book, symbolizing his commitment to Christianity. His legacy continues to inspire devotion among believers, and he is considered a protector against evil.