Harald I of Denmark, also known as Harald Bluetooth, was a Viking king who ruled Denmark from around 958 until his death in 986. He is best known for uniting the various tribes of Denmark and converting them to Christianity, which helped to establish a more centralized kingdom. His reign marked a significant transition from paganism to Christianity in the region. Harald is often credited with the introduction of the first Danish coins and the establishment of trade routes that connected Denmark with other parts of Europe. His legacy includes the famous Jelling Stones, which commemorate his achievements and are considered important symbols of Danish history.