Yeah, so? We still came from the same kingdom. And while France became a proper kingdom, Germany splintered up into countless duchies, kingdoms and counties. A moving border in the past 1000 years is inevitable when you have one unit vs. many fragments. And not all the time it was due to conquest, although that was naturally a part of it.
And to be honest, I don't even know why we're talking about it... I haven't read the last two pages. :P
What gives?