Hermenegild

Saint Hermenegild or Ermengild, was the son of king Liuvigild of the Visigothic Kingdom in the Iberian Peninsula and southern France. He fell out with his father in 579, then revolted the following year. During his rebellion, he converted from Arianism to Chalcedonian Christianity. Hermenegild was defeated in 584 and exiled. His death was later celebrated as a martyrdom due to the influence of Pope Gregory I's Dialogues, in which he portrayed Hermenegild as a "Catholic martyr rebelling against the tyranny of an Arian father."