This is a common topic in XIX century literature. Specifically, Mark Twain's A Connecticut Yankee in King Arthur's Court and some of Jules Verne's books.

By the way, I suspect that a better way of achieving what you want is to read some original texts from that era and figure out what people of that time assumed as obviously true. As it stands, you are asking for amateur guesses about perceptions of people seven centuries ago about whom the amateurs know very little (and most of that "knowledge" comes out of Hollywood, anyway).