Prior to the First World War, one of the main concerns of the British and French were the large population that Germany could sustain and the obvious advantages when it came to dominating Europe, right?
Even after the utter destruction of the second World War, and after losing most of it's pre-wars territory, Germany right now is more populous than either the United Kingdom or France.
How long does this go back? The Modern Era? The Middle Ages? And how could a realm so divided in those eras support a larger population than the metropolises of proper nation-states and world empires at that?
It's worth noting that France was the most populous part of Europe for a very long time. According to most estimates (like the one I link here), France had more people than Germany, British Isles and Scandinavia combined until around 1450 at least.
http://www.fordham.edu/halsall/source/pop-in-eur.asp
This seems to go in waves too as you can see: Greece reached a very dense population very early on and still isn't much more than double of what it reached possibly as early as 400 BCE(!!) and might still be less than they had in 1200 AD.
This is extraordinary compared to Germany, which peaked at well past 10x what it had in 1450.