[3][4][5] In Koch's view, "these semantic and etymological aspects allow that Coil could be a legendary, or even a mythological, founder" of the dynasties that bear his name rather than a historical figure.
The genealogies give him an additional epithet or patronym, Godebog (Old Welsh: Guotepauc), meaning "Protector" or "Shelterer".
Hector Boece and Ayrshire folklore both state that Coel and his entire army perished in the Battle of Coilsfield.
According to Welsh tradition the region of Kyle was named for Coel, and a mound at Coylton in Ayrshire was regarded as his tomb.
[12] Projections back from dated individuals suggest that Coel Hen would have lived around AD 350–420, during the time of the Roman departure from Britain.
[14] It has been suggested that Coel was appointed governor of northern Britain, ruling from Eburacum (York), by Magnus Maximus.
[15] In the twelfth century, a story arose claiming that Colchester in Essex was named after a man called Coel, who was the father of Saint Helena, and therefore the grandfather of Constantine the Great.
Diana Greenway proposes it came from a lost hagiography of Helena;[21] Antonia Harbus suggests it came instead from oral tradition.
[24] In the Historia, Coel grows upset with Asclepiodotus's handling of the Diocletianic Persecution and begins a rebellion in his duchy of Caer Colun (Colchester).
Rome, apparently, is pleased that Britain has a new king, and sends senator Constantius Chlorus to negotiate with him.
The Picts and Scots fled to the hills ahead of Coel's army, who eventually set up camp at what became Coylton alongside the Water of Coyle (Ayrshire).
It is said that Coel wandered the unknown countryside until he eventually got caught in a bog at Coilsfield (in Tarbolton, Ayrshire) and drowned.