The article presents the Codices of Revúca as one of the most important sources of research on Slovak fairy tales through the interpretation of the Berona fairy tale. This topic as a whole but also in the context of the fairy tale theory is still unexplored, just like most similar manuscripts of Slovak romanticists who were at the birth of the folklore studies in their pre-scientific period. It is purposly conceived as a material study with the aim of demonstrating the need to return to archive sources and the research potential offered by such materials. It is, however, not the specific objective of this article to present an analysis of the texts quoted in the annex. The article consists of two parts. The first one evaluates the existing material base of the research on the Codices of Revúca (J. Polívka, M. Dzubáková), highlights the limitations arising from the marginalisation of the available materials, offers precise records from the Codices of Revúca on the texts for the interpretation of the fairy tale and, finally, corrects the information on one of the key texts from this source, the letter written by S. Reuss on December 17, 1843, the full translation of which forms part of the text in the annex. The second (analytical) part of the article deals with the contextualisation and comparison of three commentaries on the Berona fairy tale (S. Reuss, J. Francisci, S. Ormis). All three texts are fully available in the annex.