Coel, also called Coel Hen 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, a region of the Brittonic-speaking area of what is now northern England and southern Scotland.

Yr Hen Ogledd, or in English the Old North, is the historical region that was inhabited by the Brittonic people of sub-Roman Britain in the Early Middle Ages, now Northern England and the southern Scottish Lowlands, alongside the Celtic Kingdom of Elmet. Its population spoke a variety of the Brittonic language known as Cumbric which is closely related to, if not a dialect of Old Welsh. The people of Wales and the Hen Ogledd considered themselves to be one people, and both were referred to as Cymry ('fellow-countrymen') from the Brittonic word combrogi. The Hen Ogledd was distinct from the parts of Great Britain inhabited by the Picts, Anglo-Saxons, and Scoti.