But, as we have seen, that debate does alert us to one important similarity between Athens and Syracuse, hints that Athens may be surprised by what she finds in Sicily, and reintroduces a theme that will prove of great significance as the Sicilian narrative develops: the parallelism between the Athenian and the Persian invasions. As this theme becomes more prominent, it reinforces the feeling that Athens has overstepped both geo-graphical boundaries (6.13.1) and the limits of civilized behavior and entered a world of unbounded possibilities, either for aggrandizement, as Alcibiades suggested (6.18.2f.), or for loss, suffering, and destruction.