Starting in 1919 the inter-Nordic Norden Associations of Denmark, Norway and Sweden started a textbook revision which became mutual in the 1930s, when also Icelandic and Finnish associations had formed. This chapter examines the historiographical implications of this textbook revision where historians from the different countries in a mutual manner examined textbooks both in order to create a common Nordic history for schools, and in order to defend the national history of each nation from perceived misinterpretations in the other Nordic countries' history textbooks. The chapter suggests that the entire project was imbued with methodological nationalism in that it was nationally organised, but also in the recruitment of specific historians, unwilling to abandon, what they perceived as, the natural primacy of national history.