Porrex I was according to legend, as described by Geoffrey or Monmouth, king of Britain. He was one of the sons of Gorboduc and Judon.
When Gorboduc became old, Porrex and his brother Ferrex fought for the throne succession. Ferrex flew to Gaul, where he called for the help of the Frankish king Suhard. In the war that followed, Ferrex came to life, and the Gallic army was destroyed. Porrex called for King of the British Empire. Judon, however, avenged Ferrex's death by killing Porrex, after which the Civil War broke out of the five kings. Also see
wiki
