In copyright law, the number of cross-border issues is increasing due to the growing international interconnection of economy and society. Consequently, the preliminary question of the applicable legal system to material copyright is gaining significance. This work addresses this central issue in international copyright law. It first discusses the traditionally applied principle of protection based on the principle of territoriality and demonstrates that this principle leads to significant systematic and practical difficulties, especially in the area of the internet. Alternatives are then explored. Finally, the author's own proposal is presented, advocating for the introduction of the principle of universality and linking it to the country of origin principle.