I was inspired by the other question "Why are the German and French languages so different?". But while, for me, the answer was obvious (the Romans did not conquer most parts of today's Germany and so on), another question came into my mind and its answer is less obvious.
Firstly, take for example Germany's close neighbour France. What are Frenchmen called in other European languages?
You get the point. All of these are extremely similar to each other. But now look how the Germans are called in other languages:
Why are there so many different varieties compared to e.g. French?