I don't know much about the European church system (not that I'm supposed to know anyway, given that I'm from South Asia), but it did come up in a few chapters of our History textbook.
My teacher said this just doesn't sound right to her. I suspect it's probably because I might be using brackets too liberally.
Would it have sounded stilted if I had done something like this instead:
I don't know much about the European church system, but it did come up in a few chapters of our History textbook. It's not that I'm supposed to know anyway, given that I'm from South Asia.
I understand how brackets popping out in the middle of a long sentence can be confusing/distracting, but at the same time, I also feel it flows nicer with brackets. And it is a more accurate reflection of how my thought process had originally been.
EDIT
A bit more context:
There were only 2/3 paragraphs at best on that topic and from what I've gathered, the Church used to wield more power than any king in Europe (I've no idea how much geographic area it spans). So basically the pope (the head of the Church) ruled over all the kings and could arguably be called the "king of kings".
All of this comes immediately after the sentence in question.