Coel (Old Welsh: Coil), also called Coel Hen (Coel the Old) and King Cole, is a figure prominent in Welsh literature and legend since the Middle Ages. Early Welsh tradition knew of a Coel Hen, a c. 4th-century leader in Roman or Sub-Roman Britain and the progenitor of several kingly lines in Yr Hen Ogledd (the Old North), a region of the Brittonic-speaking area of what is now northern England and southern Scotland.
Later medieval legend told of a Coel, apparently derived from Coel Hen. He was said to be the father of Saint Helena and through her the grandfather of Roman Emperor Constantine the Great.
Other similarly named characters may be confused or conflated with the Welsh Coel. The legendary "King Coel" is sometimes supposed to be the historical basis for the popular nursery rhyme "Old King Cole", but this has been said to be unlikely.[1]