Factual error: Giuliano explains to Sarah that he thinks the world is round as though this were radical. But this was the common belief throughout the late Middle Ages. The argument was about how big the Earth was and the ignorance about the existence of a continent between Europe and Asia.

Factual error: Giuliano makes references to the invention of the telescope. Yet the invention of the telescope was at least a century after the events in the story and Galileo's experiments more than 50 years after that.