Between the 13th and 14th centuries, the government of Siena dedicated particular attention to public springs and aqueducts, especially in view of the fact that the city, lacking natural watercourses, had a particularly difficult water supply. Accompanied by an accurate hydraulic operation, testified by detailed studies of the artists-engineers of medieval Siena, the fountains were of different types, depending on their location, purpose and patronage. The present study wants to highlight the typological evolution of the hydraulic and architectural structure of the Sienese fountains built in medieval times. Some of the fountains that exist today are the result of 15th century reconstructions on a pre-existing 12th - 13th centuries system; others were rebuilt in the 19th century: we have therefore tried to trace the specific historical events, to go back to the original structure by identifying the typology and the decorative apparatus, also deepening the iconographic aspects.
