This article draws on data and research results from an ongoing research and indexing project conducted by the author in close cooperation with the Bibliothek für Bildungsgeschichtliche Forschung in Berlin (BBF). Funded by the DFG - German Research Foundation -  (04/2022-03/2025), the project "Thinking Education Across Borders"aims at the indexing, digitization, analysis, and open access provision of a unique and educationally valuable international correspondence estate. As a source corpus, this legacy offers extensive research potential on the developmental dynamics of educational theory and practice worldwide and international educational networks. It also reveals boundaries and synergies in the professional pedagogical milieu, especially  between actors in a highly visible academic pedagogical milieu and pedagogical actors who were primarily active in pedagogical fields that were more distant from universities, such as elementary school teachers, or who had a harder time gaining recognition or attention in academic milieus for various reasons (e.g., gender, social or geographic origin). By exploring these contexts, a contribution can be made to generating exemplary insights into dynamics in professional milieus more generally.
     This paper examines the development of professional identities and the opportunities for female pedagogical actors to participate and contribute  in exclusive professional pedagogical milieus in an international context in Europe, the United States, and South Africa between 1869-1929. Emphasis will be placed on what norms and conventions female actors had to comply with, or what detours they had to take or concessions they had to make in order to achieve professionalism in exclusive pedagogical milieus, to be able to be professionally effective, and to give visibility to their effectiveness. Which factors could contribute to the fact that female actors, firstly, saw themselves as pedagogical experts, secondly, that they were perceived as such, and - which is not the same thing - thirdly, that they were accepted as such? Which conflicts between different (own and foreign) professional identity attributions can be identified and described? What significance did professionalism in the sense of professional aptitude and a high professional quality of work have in this context, and what other factors (e.g., social or cultural norms and conventions) were relevant to the attribution and acceptance of professional identities. In particular, the importance and influence of connections of progressive pedagogical milieus to social reformist circles, such as the women's rights movement, will be addressed, and the role played by networks between influential, represented, and typical pedagogical actors on the one hand, and pedagogical fringe groups, or underrepresented or atypical pedagogical actors on the other, will be examined.
In this context, three aspects of diversity are addressed, which are assumed to be relevant for the development, dissemination and reception of (not only) pedagogical theory and practice and which are therefore also of importance for the attribution of pedagogical professionalism.

The study is conducted from a comparative and transcending educational history perspective. The comparative perspective approach was developed as a new research approach in the research project, taking into account the particular source material. This approach is presented in the paper. It combines hermeneutic and qualitative-quantitative methods with DH-methods.

Factors of inequality and institutional structures, that made it difficult for female pedagogues to professionalize or participate in their profession are highlighted. Three aspects of diversity are explored and it will be shown how they condition different boundaries that professional actors can be confronted with in their professional work and that can favor or impede the attribution and recognition of professional identities for different groups of actors. Examples will be used to examine the extent to which efforts to establish or recognize professional identities were possible in harmony or conflict with, for example, social or cultural (attributions of) identities, whether and to what extent such efforts may have led to the emphasis, compensation, concealment, or denial of certain aspects of social or cultural identities that were understood as significant or obstructive for the establishment or recognition of professional identities. Finally, in relation to current contexts, it will also be put up for discussion whether or to what extent the attribution and recognition of professional identity(ies) depends primarily or significantly on professional factors such as expertise and professional commitment.

The MAIN SOURCES for this contribution are historical correspondence documents, which are currently being edited, analyzed and prepared for digital publication in the course of the project that the research is part of. GRUNDIG DE VAZQUEZ, Katja (2020): Thinking Education beyond Borders – The Pedagogic Correspondence Legacy of Wilhelm Rein as an Access to Historical Transnational Contacts and Networks of Educational Reform. In: Historia Scholastica 1/2020, pp. 109-123. DOI:10.15240/tul/006/2020-1-008 KOERRENZ, R.: Reformpädagogik. Eine Einführung. Paderborn 2014. MAYER, Christine (2019): The Transnational and Transcultural: Approaches to Studying the Circulation and Transfer of Educational Knowledge. In: Fuchs, E., Roldán Vera, E. (Hrsg.): The Transnational in the History of Education. Concepts and Perspectives. Cham. eBook: https://doi.org/10.1007/978-3-030-17168-1, S. 49-68. MAYRING, P.: Qualitative Inhaltsanalyse. Grundlagen und Techniken. 12., überarbeitete Auflage. Weinheim und Basel 2015. MÜLLER, Lars (2019): Kooperatives Management geisteswissenschaftlicher Forschungsdaten. In: ABI Technik 2019, 39(3), pp.194-201. POPKEWITZ, Thomas S. (2019): Transnational as Comparative History: (Un)Thinking Difference in the Self and Others. In: Fuchs, E., Roldán Vera, E. (Hrsg.): The Transnational in the History of Education. Concepts and Perspectives. Cham. eBook: https://doi.org/10.1007/978-3-030-17168-1, S. 261-291. ROLDÁN VERA, Eugenia, FUCHS, Eckhardt (2019): Introduction: The Transnational in the History of Education. In: Fuchs, E., Roldán Vera, E. (Hrsg.): The Transnational in the History of Education. Concepts and Perspectives. Cham. eBook: https://doi.org/10.1007/978-3-030-17168-1, S. 1-47.