Medieval Glassworks in the City of Ferrara (North Eastern Italy): The Case Study of Piazza Municipale

Compositional and structural characterization was carried out on transparent glass fragments found in a brick rubbish pit discovered in basal floor of the ducal palace of Ferrara, during the excavation of Piazza Municipale. This study aims to identify raw materials and glass-working techniques through X-Ray Fluorescence (XRF) quantitative chemical analyses and semi-quantitative Scanning Electron Microscopy (SEM) observations. The studied fragments were produced using siliceous-lime sands with natron as flux, and allowed us to better understand the production technologies in a historical period of great innovation for European glass art. The numerous findings of glass fragments discovered in brick underground cellars built for the specific purpose of household rubbish of wealthy complexes in Ferrara testify a consolidated system of separate discharge of solid waste into underground containers, which were closed and sealed once filled. The high volume of the finds indicates the absence of recycling of accumulated materials due to the well-being of the city. Compositional analysis confirmed the local production of glass shops in Ferrara during the late Middle Ages, characterized by differences with the glasses of the nearby city of Venice. Morphological analyses also defined the nature and relative abundance of the products, exploring the types and compositions of the Ferrara glass art.