Where does the phrase, "Thus Endeth The Lesson" originate?

Is it from a book? A play? Of course I'm leaning toward Shakespeare at this point, that would be pretty standard for this kind of thing... A translation from Latin or Greek, perhaps? The thing has found such common use on the internet, the primary source material is never the first thing in a search. Does anybody know for certain? If possible, please point me to the exact quotation, in context, which I could perhaps cite in a bibliography. Thanks in advance!