Regarding "Three Versions of Judas" and your comments .....
Borgesian use of symbolism is incredibly amazing. It seems to have a way of coalescing from different religions and cultures and yet it still has a particularly Argentinian or South American flavor. How he does that is a marvel of intellectual and academic rigor combined with a great flair for using scholarship in a creative, original fashion.
As regards the symbology of Nils Runeberg's name, in itself, your info is most helpful, along with the way Borges combines or discombines the ancient Celtic symbology and the Christian, as per the wheel and the cross. As to the serpent, I'm not sure. I'll go back and look later.
However, now we need to look at Runeberg's character qua character, as a theological personage of the early twentieth century in Lund. (Where is Lund? I need to find out.) Anyway, by his actions and reactions, we can gather the seeds of his character and grow a plant that may or may not flower as Runeberg had intended.
The questions arise as to what kind of scholar he is, how honest both to himself and others, how dedicated to the truth or purity of his religion, i.e. Christianity, and the Church approved doctrine regarding Judas and why his betrayal was necessary.
After seeking the answers to the question of Runeberg's character, we can then ask the question of Borges. Ask where Borges places the focus of the irony, that is. Is it on Runeberg, who could have found a place among the Gnostics in Alexandria of the second century, where sects differed and contradicted themselves, even to the point that even one minor Gnostic was interpreted differently? Is it on the way Runeberg first interprets the nature of Judas' betrayal and what he sees a problem in the dogma and then his subsequent reactions? Or is it on the Church and the dogma itself? How we see Borges place the irony and remark on the characters and the symbols is the key to unlocking the story and the quintessential Borges.
Do you see where I'm going with these questions?