Eudaf Hen, supposed High-King of Britain
Mid-4th Century
(Latin: Octavius; English: Odda)

Eudaf Hen (the Old) first appears in the old Welsh mythological tale, the 'Dream of Macsen'. The future Roman Emperor, Magnus Maximus, dreamt of Eudaf's beautiful daughter, Elen Lluyddog (of the Host), and sent emissaries across the Empire to find her. She was discovered in her father's palace at Caer-Segeint (Caernarfon) where the old man sat, carving 'gwyddbwyll' pieces (like chess-men). Maximus came to Britain, married the girl and eventually inherited her father's kingdom, much to the disgust of his male heir, Conan Meriadoc.

It is tempting to imagine that Eudaf was some kind of client-king or tribal leader or perhaps a local decurion living in mid-4th century Roman Britain. If he existed in some form, he would have been a Briton living an extremely Romanized lifestyle. Octavius may have been his formal name. His daughter would have been Helena.

The dream story clearly indicates that Octavius was influential around Caernarfon in North Wales, but later writers - chiefly the mistrusted Geoffrey of Monmouth - made him "Duke of the Giwissei" or "Iarl Ergyng ac Ewias": evidently ruling in Ergyng and Gwent. This idea may have arisen from his supposed descent from pre-Roman Kings of the Silures tribe who lived in the same area. The connection is persistent and it is equally possible that the Caernarfon association is merely due to Maximus and Helena's later residence there. The Roman official with control of both the Caernarfon and Gwent areas was the Praeses of Britannia Prima. An association with such a high rank might explain why Octavius was remembered as a 'High-King'. Geoffrey's mythology has Octavius taking up this British High-Kingship after defeating King Coel Godhebog (the Magnificent)'s brother, Trahearn, in battle near Winchester. So perhaps he took office by force.

Early legends are confused about Eudaf's descendants. Some stories claim that he had various sons, Conan, Adeon/Gadeon and Eudaf II. Others, that Helena was his sole direct heiress and that Conan, his male heir, was only his nephew. This appears to fit best. Magnus Maximus and his wife could have inherited Eudaf's position in society, helping the former to put himself forward as Emperor of the West. Conan supposedly made excellent marriages and was placated with vast estates given by his cousin's husband. Adeon/Gadeon alias Cadfan was probably his son. Eudaf II appears very late and is probably fictitious.