Studies on minorities' issues have mostly focused on conflicts rather then on solutions. Yet, this project puts the emphasis on the development of concepts of personal autonomy in the first decades of the 20th century. Personal autonomy is a non-territorial form of self-rule including all members of a national minority regardless of their place of residence. To compile such a member list, all citizens had to register in national cadasters. Of course, difficulties to classify people occurred; furthermore, these registers also accelerated the ethnification of the whole population, because they forced every citizen to follow the logic of nationalism. I will first analyze various theories and several implementations of personal autonomy regulations in the Habsburg Empire. Secondly, I want to trace continuities and changes of this idea in the interwar period. Finally, I will try to evaluate the experiences from implemented personal autonomy provisions and their influence on European societies.