Constructing Siena Cathedral. Sources and Observations on the Use of Brick in the Middle Ages

As part of the comprehensive research project Die Kirchen von Siena, realised by the Kunsthistorisches Institut in Florenz, Siena cathedral S. Maria Assunta or Our Lady of the Assumption was studied within the last years by an interdisciplinary group of scholars, including art and architectural historians as well as archivists. The appropriate archive of the Opera di Santa Maria di Siena, nowadays Opera della Metropolitana, is numbered among the richest and most complete mediaeval archives in Italy; it allows a widespread view on the organisation of the building site, on payments and on the providing of material. But the archival tradition needs to be confronted with observations of the building itself – and, of course, converse: Is there an archival evidence for an architectural observation? The paper discusses possibilities and limits of an interdisciplinary research into Siena cathedral, confronting sources and building observations on the use of brick as a both well documented and researched sample.