One of my all-time favorite books. The most impressive part of this book is the lack of anachronisms. You feel like you're literally in the mind if a 14th century monk with all the worldviews and biases that go with it.
Have Wikipedia and Google translate open unless you're an accomplished polyglot of Indo-European languages. Eco was an erudite scholar of languages, history, and literature, and he doesn't hold back or dumb anything down.