"Ah!" Harry says, delighted, as he opens the book. "Why, 'tis Northumberland!"

Well, the landscape seems to be, anyway. But the land within it is marked into territories he does not recognize-- and he realizes that there are little army encampments featured, too, attributed to lords whose names he doesn't recognize. And as he watches, the little x's marking the troops shift and change, the little pennants move forward and back-- they're fighting, right there on the page, and as lands are won and lost, the borders shift accordingly, right there on the page.

Gaping, he holds the book out for Bahorel to see.