Did King Digueillus from Geoffrey of Monmouth’s HRB Really Exist?

In Geoffrey of Monmouth’s Historia Regum Britanniae, the grandfather of Cassivellaunus was a certain King Digueillus. Can he be identified as a historical figure? This video makes the argument that he can.
To learn more about the historicity of the Historia Regum Britanniae, check out my book, King Arthur: The Man Who Conquered Europe: www.amberley-b...