When authors refer to other great works, people, and events, it’s usually not accidental. Put on your super-sleuth hat and figure out why.
Turns out that since Tortall is a made-up fantasyland, the book doesn't contain a lot of references to stuff in our world. Imagine that! There are some general crossovers, like ideas associated with feudalism (kings, knights, and so on), but no references to specific things like novels or philosophers. Some of the names, like Mithros and Persopolis, are based on stuff here, but that's about it. (Though we wouldn't be surprised to find out that Duke Roger used magic to get on the Internet and make captions for Grumpy Cat)