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), the Brittonic-speaking part 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.