Torcello is the name of an island in the Venetian lagoon, where evidence for the development of Venetian glass-making arising from that of the Romans has been identified.
Archaeological investigations in the Venetian lagoon are generally impeded by the rising water, and it is recognized that prehistoric occupations probably exist below the oldest known strata.
The earliest architectural ruins on Torcello are dated to the 2nd century AD and were discovered during rescue investigations of the 8th century AD Byzantine basilica of Santa Maria dell'Assunta. These ruins include a narrow walkway laid on the top of the natural land surface, and a small room and hearth dated to the 6th century AD. The foundations of the Basilica were laid around 700 AD.
Glass Making at Torcello
Archaeological evidence suggests that Torcello was occupied by the Romans at least by the first century AD. Evidence for glass-working, in the form of crucibles, flat glass, glass waste, vessels and sherds, and tesserae from mosaics, have been consistently found in levels dated between 7th and the 13th centuries. A glass-making furnace, with chambers for fritting and annealing, has been discovered and securely dated to the 7th-8th century AD. The structure conforms mostly to Roman concepts of furnace construction, rather than later Venetian manufacturing constructs.
Chemical investigation of the various glasses from different levels at Torcello indicates a slow transformation of glass techniques from Roman natron-based glass to what would become Venetian soda-ash based glass. The soda-ash based production allows the creation of an opaque glass for the first time.
Interestingly, this transition occurred in the 12th-13th centuries, after the production of the mosaic works of the Santa Maria Assunta basilica. Researches believe the opaque glass used for the mosaics must have been created at an unknown Levantine site, and reworked into the mosaics at Torcello.
Sources
Broad, William J. 2000. That Sinking Feeling, Again. New York Times August 29, 2000.
De Min, Maurizia. New Archaeological Evidence from the Sites of Torcello and San Francesco del Deserto in the Northern Lagoon (abstract)
Roe, M., et al. 2006 Characterisation of archaeological glass mosaics by electron microscopy and X-ray microanalysis. Journal of Physics: Conference Series 26:351-354.
Verità, Marco, Alessandro Renier, and Sandro Zecchin 2002 Chemical analyses of ancient glass findings excavated in the Venetian lagoon. Journal of Cultural Heritage 3:261–271.
This glossary entry is part of the Dictionary of Archaeology.
