Known in other histories as Coel Hen Godhebog, Coel founded the city of Colchester that still bears his name (Kaercolim). His daughter, Helen, was married to Constantius, a Roman Senator, who was sent to Britain as legate. He became king on Coel's death.
Coel was a British King, whose capital was Colchester. He married his daughter Helena to a Roman general and she subsequently became mother to the Emperor Constantine and was subsequently declared as saint for her work in spreading Christianity. Presumably Coel's good humour relates to the peace his daughter's marriage brought to his kingdom.