My novel: readings and misreadings

I've had good response from agents to my queries regarding A Gift for the Sultan, my novel about the siege of Constantinople in 1402. However, I was a little perplexed by comments from one agent who read almost the entire text (mysteriously, the last 15 pages were missing from her copy, but she has since received them). She seemed to like it, but she wasn't sure who was the hero or heroine. She decided it was the princess, and was wondering what happens to her at the end.

I may need to make things clearer in my synopsis. To my mind, the protagonist of the story is not any individual but the city, Constantinople, which uses the princess (and many other characters, including foreign mercenaries, merchants, and a gang of juvenile delinquents) to save itself. The central conflict is city vs. anti-city, the latter represented by the Islamic horde (literally; that's ordu in Turkish) of the Ottoman sultan. There is a romance within the novel (beautiful blond princess meets swarthy mounted warrior), but it's not a romance novel. It is, I guess, a political, or maybe a macrosociological novel, not about an individual but about two much larger collectivities -- the city and its enemies -- within which individuals are forced to maneuver. I hope the agent sees that now that she has the final pages. Just exactly what happened to the princess remains ambiguous -- because it is that ambiguity that serves the city (different versions for different factions, which is how all great cities maintain their urban mystique). How the city saved itself, though, is very clear.