The article reconstructs the context of political conditions and ethical concerns within which Momigliano's methodological reflection on historiography was formed. This context is first examined by comparing Momigliano with two different types of historicism, namely the old continental historicism, with particular reference to that of Italy, and different versions of the new anglophone historicism. The study goes on to focus on the theories and the reasons that lie behind Momigliano's divergence from Finley regarding the legacy left behind by the Greek world for those of the modern age, and their concept of liberty. The nucleus of Momigliano's reflection on the practices and rules of historical research is identified through the elaboration and the use of the "model of the historical situation" concept, which has its origins in Droyson. The case put forward by the article is that this concept represents Momigliano's response to practical historiographical needs in the treatment of the two connected problems of conflict and change, but that it also responds to an ethical-political concern which is universalist in nature.