Olympiodorus (A.D. 425).
'Hist. Nov.' vi. 10. He is a contemporary authority.
Tennyson, 'Guinevere,' 594. The dragon standard first came into use amongst the Imperial insignia under Augustus, and the red dragon is mentioned by Nennius as already the emblem of Briton as opposed to Saxon. The mediaeval Welsh poems speak of the legendary Uther, father of Arthur, as "Pendragon," equivalent to Head-Prince, of Britain.
See Rhys, 'Celtic Britain,' pp. 116, 136.