Cyllin was a legendary, and possibly historical British king of the 1st century AD, early Christian saint and the last pendragon of Great Britain.
[1] Richard Williams Morgan claimed that a reference to him as a son of Caratacus was found in the family records of Iestyn ab Gwrgant and used this as evidence of early entry of Christianity to Britain; Cyllin ab Caradog, a wise and just king.
In his days many of the Cymry embraced the faith in Christ through the teaching of the saints of Cor-Eurgain, and many godly men from the countries of Greece and Rome were in Cambria.
[2]Reference to Cyllin is also given in Iolo Morganwg's "Third series" of forged Welsh Triads.
[3] He is also discussed in the works of Rice Rees, Jane Williams, Sabine Baring-Gould and John Williams (Ab Ithel) as brother of Saint Eigen and father of King Coel.