That's what I figured:
"Naturally I taught my students Thomas Aquinas, but I found it difficult to do so. The problem was that his arguments presented such a strong appearance of truth. For the very beauty of this appearance, I had to exercise strong discipline not to weep. One of my students in those days asked permission to put a personal question. "I’ve been listening carefully," he said, "and I figure that you’re either an atheist or a Roman Catholic. Which one is it?"
You can see why, when I finally returned to Christian faith, I wanted that one foot in Catholic tradition."
And the rest as they say, is history. Aquinas may be among the most underrated thinkers in the minds of modern folk. Oh that's right, we're "enlightened". Calvin runs a very close second.