Where does the medieval glass from San Genesio (Pisa, Italy) come from?

The aims of the research are to provide elements and collect information, using an interdisciplinary approach (electron microprobe, SEM-EDS), in order to formulate hypotheses regarding the provenance of some cups and lamps, dated from 9th to 13th century and found in the medieval site of San Genesio (Pisa, Italy).The results show that: - they are not local productions; - in Tuscany there were a slow transition from natron to plant ash production technology typical of the 11th and the 13/14th centuries, and a long coexistence of natron glass, plant ash glass and an intermediate composition