Duns Scotus. Educated in Oxford and Professor of theology in Paris. Apparently his intellect was a miracle, as he was slow as a child and prayed for wisdom. He was a mystic and a philosopher. The poet is referring to this experience in the poem.
What is the link between a Fairport convention song, with the mythic power akin to that of Oedipus, and a poem by Hopkins?
In this case, it is a saint: not a man who did great things, but a man who helped many by suffering greatly.