He was off to a poor start as the illegitimate son of a prostitute. Having to work long hours at an inn, he found that he was welcome to stay overnight at a shrine — which gave him an insight into the Holy World.
This seemed to be much more to his taste, so he took instruction and got himself ordained.
He then found he had special gifts of exorcising demons. This got him the nickname of ‘Iron Eater’ — although we’re not sure what iron has to do with either demons or exorcism.
After this he rose swiftly through the ranks to become Bishop of Anastasiopolis. When the administrative duties became too much he returned to a quiet monastery to do spiritual healing and the other things he was so good at. Including eating iron.