Everything you need to understand or teach The Discarded Image by C. S. Lewis.
The beliefs of the Medievals might in some respects resemble those of less civilized peoples. What distinguishes them, however, is that while the beliefs of "barbaric" peoples are ultimately derived from their immediate environments, the Medievals were almost obsessed with books, and their beliefs can all be traced to the authority of some author, for better or worse. Many of these writers, like Cicero and Lucan, were not even Christians, though...
The Discarded Image: An Introduction to Medieval and Renaissance Literature Lesson Plans contain 118 pages of teaching material, including: