Emperor Constantine III
(c.AD 375 - 411)
(Welsh: Custennin; Latin: Constantinus; English: Constantine)

After the gradual withdrawal of Roman troops from Britain in the last decades of the 4th century, several generals rose to power as Emperors over the mainland British. Legend, particularly perpetrated by Geoffrey of Monmouth, states that the British people looked to their cousins in Brittany for such leadership. It is said that King Aldrien of Brittany declined the British High-Throne, although his existence is in considerable doubt. Perhaps some other Breton king was meant. Traditionally he offered up his young brother, Constantine, in his stead. Constantine apparently landed in Britain with 2000 men and overcame the barbarians already invading the Island's shores to become High-King as Constantine Waredwr (the Deliverer).

Constantine has been variously identified with one of several near contemporary men of this name appearing in ancient Welsh royal pedigrees: the Galfridian brother of King Aldrien of Brittany, a son of the Emperor Magnus Maximus or a King of Dumnonia in South-Western Britain. The latter is perhaps the most popular, yet also the most unlikely and based on his traditional grandson Arthur's associations with Somerset and Cornwall. Our character's alternative name of Constantine Fendigaid (the Blessed) may itself have appeared through confusion with one of these men.

It seems likely that this man has arisen to take his place in British mythology from memories of an historical British Emperor who was raised to the Imperial Throne by his own troops in AD 407. Disenchanted with the rule of the legitimate Emperor Honorius, the Roman army remaining in Britain had already got through two self-appointed emperors in a single year. Worried about renewed barbarian invasions on the Continent, they decided to promote the usurpation of a third in the shape of the Emperor Constantine III. From his base in Britain, Constantine was able to take perhaps the last of the Roman troops in that province to Gaul. There he strengthened defences along the Rhine and was able to head off the Barabrians who, two years later, turned south for Spain. Constantine sent his lieutenant, named Gerontius, to counteract their move; but Gerontius rebelled against his Emperor and encouraged the Barbarians in their efforts. Despite this renewed attack, Constantine gained Imperial recognition from the Emperor Honorius himself. However, his position was soon discredited and Zosimus tells us how the British were forced to throw off the shackles of Imperial rule and look to their own defence against invading Anglo-Saxons. Constantine tried to assert his authority once more by invading Italy in AD 411. He was captured by Honorius at Arles, taken back to Ravenna and executed..

It is possible that while all this was going on on the Continent, Constantine was deposed in Britain by his treacherous advisor, Vortigern, as related by Geoffrey. However, it would appear that he has pushed Constantine forward in history some fifteen years or more. If the Emperor's descendancy is to be believed, his grandson, King Arthur, was flourishing almost a hundred years after his death.