The issue covered in the title of the proposed paper has not yet been comprehensively, multidimensionally and modernly studied in the form of a uniform monograph, either in Polish or foreign historiography. Meanwhile, this is an important problem that undoubtedly deserves thorough study and presentation within an appropriately broad analytical framework, using universal historical analogies. In my speech, I intend to share with the audience the results of my over ten-year research on the visits of legates and envoys of the Holy See to Poland during the reign of the Piast dynasty. Since my research is aimed at a future monograph on the subject, it seems reasonable to collect in one place and in a synthetic form what has been established so far through collective effort, and then indicate which topics still require reflection and discussion. I will conclude my paper with a presentation of the project of the planned dissertation together with the research method and its questionnaire.
