I really admire the amount of research you do for your stories. Especially history offers a lot of material, so kudos for not getting lost in it. What I´d like to know: Do you have the story in mind before you start the research, or does the story come with the research?
A little bit of both. I begin the process with some general ideas and themes—for example, Dante, Florence, overpopulation. Before beginning to write, I spend a lot of time researching the topics I’ve chosen. Once this initial phase of exploratory research is complete, I use the information to begin outlining and writing the novel. As the story gets tightened, the research continues, and new discoveries often pull me in unexpected directions, causing me to add another twist or two.