So, Germany previously had Prussia, Bavaria and the rest. They were separate kingdoms, but all ethnically German.

There is something to be said of for the individual cultures being even stronger during those times. Perhaps the formation of the German nation state was a counter reaction to the Napoleonic wars?

Anyway, this has little to do with immigration from all over the world: All these kingdoms already had the same language and largely the same culture.

Thank you. I wouldn't exactly call France a tiny state. Are there any others that I should specifically be looking at? The Europeans pride themselves as being quote unquote civilized people, did they not have uniform ethnicities within their borders before the founding of their states? If not, then what did define those borders?

Have states such as France ethnically cleansed other peoples from within their borders? If so, then why isn't that mentioned in the well-known histories?