What was Constantine's mother credited for?

Constantine's mother, Helena, is credited with several significant contributions to Christianity. She is often recognized for her role in promoting the faith during her son's reign, particularly through her efforts to locate and preserve Christian relics, including the True Cross. Helena is also credited with influencing Constantine to issue the Edict of Milan in 313 AD, which granted religious tolerance to Christians in the Roman Empire. Her legacy includes the establishment of churches and pilgrimage sites in the Holy Land, which remain important to this day.