Enniaunus was a legendary king of the Britons as accounted by Geoffrey of Monmouth. He was the son of King Archgallo and brother of Marganus II. According to Geoffrey, he ruled poorly and harshly causing him to be deposed due to tyranny. He was replaced with his cousin Idvallo. The term Briton may have the following meanings: in a historical context: an inhabitant of Great Britain in pre-Roman times a descendant of Britons during a later period (e. ... Geoffrey of Monmouth (in Welsh: Gruffudd ap Arthur or Sieffre o Fynwy) (c. ... Archgallo (Welsh: Arthal) was a legendary king of the Britons as accounted by Geoffrey of Monmouth. ... Marganus II was a legendary king of the Britons as accounted by Geoffrey of Monmouth. ... Idvallo was a legendary king of the Britons as accounted by Geoffrey of Monmouth. ...