All literature draws from the record of stories and events that has preceded it. English and American literature primarily draws inspiration from the stories of Western civilization, grounded in the the Judeo-Christian ethic, as well as Greek and Roman history. Thus, the challenge for many readers - and students in the high school classroom - is accessing the texts with enough prior knowledge to recognize the allusions and "get the point." As an English teacher, I often tell my students they need to be on their way to becoming - in the words of Henry James - people "on whom nothing is lost."
In the past few years, my colleagues and I have discussed the challenges of engaging students in classic literature when there is so much that is no longer common knowledge. At the AP level especially, teachers speak at conferences about how much students need to know - and the disconnect from their actual store of knowledge. To that end, we began compiling a list of allusions and references that students may encounter and might need to know. Certainly, the lists of "cultural knowledge" the E.D Hirsch has assembled for his book Cultural Literacy: What Every American Needs to Know is a foundation and the gold standard. In fact, it forms the curriculum of many schools that adopt the Core Knowledge movement. For others, a more abbreviated list is perhaps more practical.
To that end, I developed a list of common cultural allusions, and we have made it a part of the English handbook. The abbreviated list has background info, and it is divided into sections on:
Greek and Roman myths
Major historical events
Pop culture references