How did the peace treaties made after WWI both follow and violate the principle of self determination?
One the one hand, these treaties did create more instances in which national groups got the right to self-determination. This can be seen most clearly in the break up of the Austria-Hungarian Empire. This empire was split up and countries like Czechoslovakia and what became Yugoslavia were created and countries like Romania were enlarged. At the same time, however, many people were left in countries not run by their own ethnic groups. This happened to Germans and Hungarians in particular. In addition, the treaties did not allow for any sort of self-determination for the people living in the colonies of the various empires. People living in the old Ottoman Empire, for example, were put under League of Nations mandates, not given their own independent countries.