According to Irish stories of saints, Christopher is born a pagan Dog-head called Reprobus. He regrets his beastial nature and is overjoyed when his conversion to Christianity allows him to lose his Cynocephalic nature. An eighth-century list of Saints explained that Christopher "was one of the Dog-heads, a race that had the heads of dogs and ate human flesh. He meditated much on God, but at that time could only speak the language of the Dog-heads."As time passed, the writings mentioned less and less of Christopher's Cynocephalic nature. Walter of Speyer wrote, in the tenth century, stated that Christopher "took his origins from the Cynocephali, a people in speech and countanence dissimilar to others."Sait Christopher was more popularly pictured as a giant carrying the christ child. This still satisfied that Christopher was a convert from a monstrous race. But it was probably more due to the fact that Christopher literally means Christ carrier.

It is plain that this is not quite the patron saint of travelers that we are told about at Sunday School. It is a peculiarly Old English view of St Christopher. He resembles the monstrous Healfhundingas, a race mentioned in two Old English texts: The Wonders of the East and The Letter of Alexander to Aristotle. More to the point, he resembles the lupine monsters of Beowulf.

Like most other Indo-European traditions, the Germans seem to have conceived of an otherworldly ferryman who conducted the dead to the underworld; indeed, Odin was so pictured during the Viking Age. It seems reasonable to suppose that St Christopher's occupation and location struck a traditional chord familiar to Anglo-Saxon ears, and that the legend was consequently coloured by Germanic underworld motifs.

Other conversions of dogheads include a saint or two. Saint Mercurius (not well known in western tradition, mostly in greek and egeyptian accounts) used converted Cynocephali as soldiers.