Strips

It an historic reference to when the Ottoman Turks overthrew Byzantine Empire in 1453. While Constantinople fell the Christian theologians were closed up inside the church debating how many angels could fit on the head of a pin.
I'm amazed that Ratbert even knew that. Or maybe with him it was just a wild stab in the dark and he actually hit upon something.

With much embarrassment, I admit I still don't get it. Could somebody please explicate?

Thanks 76kombi, I didn't catch that one at first.