The article aims to show how ethnographic data concerning religious rites, both Catholic and pagan, circulate in culture and thus become a kind of historical source for re-enacting other, invented religious rites. In the example of the Rękawka fair in Cracow, it is demonstrated how religious content present in nineteenth-century ethnographic descriptions, originally ascribed to pre-Christian paganism but incorporated into a Catholic fair, was separated from it and used in recreating and performing a neopagan rite. Investigating an Early Middle Ages re-enactment movement, the author focuses on the process of transforming ethnographic data into historical ones. Analysing the problem of authenticity of such sources, she points out the particularities of achieving authenticity in a re-enactment movement: to some, the contemporary Rękawka fair remains only a kind of historical re-enactment, while according to others it is a true neopagan rite.