Today, pressing security problems result from fragile statehood, and thus state-building has become a core responsibility of the international community. Ideally, such an intervention provides a short-cut to consolidated statehood; however, de facto, it has often failed. Countless studies have analyzed mechanisms accounting for the success or failure of state-building, but no clear picture has yet emerged. Strikingly, the debate widely disregards the historical records of state formation, even though these interventions aim for similar results. Bringing a classical state formation perspective back in, this paper bridges the state-building/state formation divide in research and asks the question: how do successful processes of state formation develop and what do they tell us about state-building operations? I analyze two cases of successful endogenous state formation in a non-Western post-conflict context. Scholarly work explaining the development of statehood distinguishes two broad groups of arguments: bellicose and cooperative theories. I demonstrate that state formation in Eritrea resulted from imperatives of warfare, while the state in Somaliland is owed to an elite coalition. I argue that there is little scope to steer and advance such state formation trajectories by liberal interventionist state-building. The logic of these operations conflicts with the internal dynamics of the two pathways. However, less intrusive intervention might facilitate domestic coalitions.