Dionotus

In Geoffrey of Monmouth's Historia regum Britanniae, whose account of the rulers of Britain is based on ancient Welsh sources disputed by many historians, Dionotus was a "legendary" King of the Britons during the campaigns in Gaul led by Emperor Magnus Maximus. The curious thing about this king is that the Welsh chronicles, which parallel most of Monmouth's book, does not mention this king by name although Monmouth uses Latin versions of Welsh names so he could be referring to Dynod, duke of Cornwall or Anwn Dynod, Maximus' own son. He succeeded his brother, Caradocus as ruler of the Britons and Cornwall. The latter would probably be Conan Meriadoc another son of Caradoc of Cornwall.