There's a famous quote from William Faulkner: "The past is never dead. It's not even past." That's a pretty good summary of how the past works in A Game of Thrones. It's like throwing a rock into a pond. Let's call that rock "Robert's rebellion against the Targaryens": the rock may be in the pond already, but the ripples are still going out. And it's not just recent history that has ripples – some ancient, ancient history seems to be returning, too (the return of the Others in the north and the re-birth of dragons in the east). In A Game of Thrones, the past is rapidly catching up with the present.