It's on the top of a small mountain that lies at the foothills of a larger mountain range. Geographically, it is fictional, but the people are supposed to bear a parallel culture to the Holy Roman Empire so it would be somewhere Germany-ish. The time period actually fluctuates throughout the story since some of it is from the perspective a monk who lived there and some of it is from a boy at the boarding school. The monk is the middle ages, the boy is around the 1960s.