The Composition of Byzantine Glass
International Network Sponsored by
The Leverhulme Trust 2007-2010
Mosaics are perhaps the most outstanding examples of Byzantine art
which survive, yet we know next to nothing about how they were made.
One of the most important gaps in the study of Byzantine mosaics
lies in our understanding of the manufacture of the medium of their
composition. Glass-making was a relatively sophisticated skill in
the mediaeval world, yet no written documents survive from Byzantium
about the methods used for making a mosaic or creating its tesserae,
and we have no knowledge of the ways in which manufacturing patterns
existed and changed over time, or, indeed, of where and exactly
how tesserae were created. Only the mosaics themselves speak to
their composition. We know that glass making and glass working were
two distinct processes, but did the differently coloured glass tesserae
on one site all come from the same batch of raw glass? Where did
that raw glass come from? The nature of the actual colours used
in making mosaics changed over time: is this simply a question of
changing aesthetics or are there also technical explanations for
To discuss questions like these, we are running a series of workshops.
We hope that these will not only provide answers to central questions
about artistic practices, but will also feed both information and
analysis into wider debates about the nature of trade and exchange
within the Mediterranean during this period and into our understanding
of political and social changes within the Mediterranean world.
From a study of the distribution patterns of glass tesserae, can
we, for example, gain any sense of how the sourcing of raw materials
for glass-making changed over time? One thing we are particularly
keen to explore is the possibility of collating evidence about the
chemical make-up of glass tesserae, which might then make it possible
to build up a pattern of both mosaic and glass manufacture within
the Mediterranean throughout the Middle Ages.
It is a project that can only be accomplished with collaboration
across disciplines and scholars: no single person has the tremendous
breadth of knowledge that would be required to tackle this field
alone. Consequently, the network, which cuts across art history,
archaeology, chemistry, physics and Byzantine studies, brings together
a range of scholars from Europe and America interested in the chemical
and physical analysis of Byzantine glass together with those concerned
with the formal and cultural aspects of Byzantine mosaics in order
to reappraise mosaics and mosaic making in this interdisciplinary
context. The programme aims to draw together scholars who work on
different aspects of glass mosaic production and analysis from the
scientific and art historic worlds, but who rarely, if ever, meet
and discuss their common concerns.
Workshops during 2007-2010 in London, Ravenna, Athens and Thessaloniki
will address technical questions about the manufacture and distribution
of coloured glass mosaic tesserae. One of the key objectives is
to establish a common framework for the testing of glass and the
comparison of the scientific data obtained from testing. Another
is to set up a centralised record of information of this nature,
in order to facilitate its comparison. The workshops will also discuss
questions beyond the purely technical. In particular, they will
address issues of whether patterns occur in the distribution and
colours of Byzantine mosaic glass. By collating evidence it should
become possible to build up a pattern of mosaic and, further, glass
manufacture within the Mediterranean throughout the Middle Ages.
We are grateful to The Leverhulme Trust for undertaking the funding
of this International Network.
The Project is directed from Sussex by Prof. Liz James (Department
of Art History, University of Sussex and Sussex Centre for Byzantine
For further information visit our website.
See also Liz James's excellent 2006 paper Byzantine
The Network is housed in the Sussex Centre for Byzantine Cultural
History at the University of Sussex. If you are interested in joining
the Network or want more information please contact Liz James (01273
873611) or Network Facilitator Bente Bjornholt (01237 873038).