Territorial secession and dissolution of empire means a challenge to the established system of states. How are the criteria for recognition of new states worked out? How is the gatekeeping to statehood performed? We shall sort out the answers by putting the new post-Cold War challenge into historical perspective. It is not only a question of changing criteria of entry to the system of states, but also one of a change in the state system whereby the quest for ‘criteria of admission’ became meaningful. The question of ‘gatekeeping’ is therefore intrinsically linked up with the modern evolution of the state system as such. The article is structured in a way that will specify this linkage historically.