Defining Hybrid Spaces for a Medieval Thermal Spa. The Case of the ‘Caldanelle di Petriolo’ (Italy)

The ‘Caldanelle di Petriolo’ is a medieval thermal site on the Farma River, part of the Mount Amiata hydrothermal district in southern Tuscany. It provides an exceptional archaeological context for examining “hybrid space” as the interplay of architectural design, hydrothermal technology, and social practice. Excavations document an articulated built ensemble whose layout and uses evolved between the fourteenth and seventeenth centuries. Rather than a marginal annex to the nearby baths of Petriolo, the Caldanelle appears as an integrated undertaking in which hot mineral water structured therapeutic practices, domestic and hospitality routines, as well as productive activities. Drawing together architectural analysis, material culture, and written evidence, the article reconstructs its development, spatial organisation, and position within a wider European repertoire of thermal architecture.