Reflection on the treatment of Reformation literature in primary and secondary school is a didactic challenge from at least two points of view: Firstly because this literature is difficult; it is incomprehensible to school pupils both due to the language and to cultural, structural and numerous other unknowns. At the same time, due to its constitutive contribution to Slovene culture and nationality, it is one of the dimensions of Slovene cultural heritage that must be taught in the Slovene school. In Primož Trubar's jubilee year, and some months before, I therefore planned a two-part pilot research project with the following two research questions: - What is the durability and quality of the knowledge of primary and secondary school pupils about the Reformation, and on what levels are the weakest pointsof this knowledge? - Which didactic approaches would most adequately address any weak points that emerge? The subject didactics adopts a sensible approach to answering these questions, with two main phases. The first is a kind of 'diagnosis', i.e., determining the actual state and the weak points amongst the pupils, while the second is a 'therapy', i.e., designing didactic guidelines in the form of applicable principles or a more concrete exemplary model of treatment. In the present article the first key phase is treated: a diagnosis of the durable and quality knowledge of primary and secondary school pupils about the Slovene Reformation. After determining the deficiencies in the durable and quality knowledge amongst pupils (the intercultural and critical connection of information, an understanding and positioning of Protestant texts) a suggestion for didactic solutions is added.