Not really adding anything, because I’m not in a great position to go back and re-read and re-examine, but how, when I was reading Julian, did I not think to go back and look at it Pater’s Marius!
Both are about Roman aristocrats from late antiquity with pretensions towards philosophy. Marius, of course, goes from living as a pagan (or, as Julian would have called, a Hellenic) to becoming a Christian, whereas Julian was raised in a rapidly Christianizing empire, but chose to adopt the gods of his ancestors.
A missed opportunity. I did see Marius sitting on my shelf, however, and maybe I will try and go back while Julian is more or less fresh in my mind.