Don't quite recall, but I think it was from a book about cathedral builders or something. But I'll admit my knowledge of medieval guilds is largely superficial and drawn from books where it was a side issue rather than the main topic. Your description sounds like you know what you're talking about. Got any good references (books, not articles) worth reading to get a clearer idea of how guild economies worked?
I'm not an expert: I spent a bit of time about ten years ago researching the topic, back when there was a lot of talk about guild structures being appropriate to software development.
