Based on the study of a peculiar Wallachian estate of the kings of Hungary in Transylvania, the book represents the first analysis in an international language of Greek rite ecclesiastical structures and political actions in the eastern parts of the Latin rite Kingdom of Hungary at the end of the Middle Ages. Primarily devoted to often neglected or marginalised medieval information, the analysis also focuses on the ways in which 19th and 20th century confessional and national policies tailored the still extant medieval sources.