First, read the Introduction and see how the folk tale and wisdom literature elements are presented. If your students are interested in this, there is a wealth of material for them to use in writing/researching a paper on many of the stories.
Second, in a multi-level class, you can have all the students read the actual Alphonsus story, then have the more advanced students read either the Gesta versions or the other Latin sources that are presented with each story. The less advanced students can read about the wisdom/folk tale origins in English and add their commentary.
You can also have students write their own moral to the story, whether it’s the Alphonsus or the Gesta version.
Second, explain to the students that they now have a chance to understand the medieval mind. Things that we see know are not possible (e.g., a column rising in the middle of the ocean) were perfectly reasonable to the time period. If students look at some of the old maps, they will see lots of fantastic items listed. It’s not that these people were “stupid,” it’s that their understanding of the world allowed the mystic and the real to coexist on the same plane.
Students love this book, which can be read on many levels. First, it is a science-fiction story: the protagonists travel to strange new worlds, and do indeed seek out new lives and new civilizations; they boldly go where only one person had gone before (to paraphrase Star Trek). Certainly a demon leaping out of a person’s mouth, spending a year on an island and thinking that only a day has gone by, and finding people who are over 120 years old is not in the realm of reality, not to mention finding a “grail”.
Third, it gives us a different view on the Medieval and early modern world. That cartographers thought there really was a St. Brendan’s island (see illustration and note on p. iv) is surprising to us, with our rational minds. However, we see the world differently than they did, and it is always important to remember the time and context of a work.