In the late nineteen-eighties, I spent a semester in Florence, where I sat in on a Dante course at the university. The entire term was devoted to the analysis of a single canto. As it happened, the canto was Inferno 19, which is devoted to simony. Dante reserves a special hole in the third sub-circle of the eighth circle of Hell for corrupt Popes; they are stuffed into it, one after another, headfirst. Their feet are then lit on fire. Among the issues the class discussed at length was how, exactly, new Popes could be accommodated. Had space been left open for all those that would come along? Or did each new arrival compress his predecessor into some kind of pontifical pesto?