Well, in the far past both of our nations could've been bigger than they are now. Could even say that one of us had a vassal nation that got caught up in it, got devastated, then was annexed by the lord nation just to survive; that vassal nation could take up a chunk of the space between us. 

Actually, if we're going that far back, Arman-Arhus wouldn't have been a Commonwealth quite yet. They'd be very close allies, but still technically two separate Kingdoms, even the union wouldn't have happened yet then. But I'm fine either way in terms of war or cold war; definitely makes that trade route interesting.