From the twelfth to the sixteenth century, Florence was the site of some of the most important experiments in knowledge production and creativity that ultimately impacted the development of many aspects of modern Western culture. Between a proto- capitalist economy, political self-governance, and artistic and architectural revolution, Florence has produced a vast documentary record that is still largely extant and is unequaled by virtually any other European city. Over several centuries, large quantities of the documents housed in the city’s numerous archives have been transcribed, translated, published, and deployed by scholars of numerous historical and sociological disciplines working all over the world. Notably, many of these documents remain in manuscript form and many have not been read in centuries, if in fact they were ever studied at all. As such, the Florentine documentary archive constitutes a unique and invaluable pre-modern site for the application of digitally based mapping and network analysis techniques. This systematic approach to analyzing communities and social networks over time through the examination of archival documents derives the historian David Herlihy’s application of the most advanced computer computational technologies available in the 1970s to the rich demographic data provided by Florence’s comprehensive fifteenth- century tax declarations and assessments of its entire dominion. Known as the Catasto, this series of documents was at the heart of the groundbreaking collaborative publication of Toscans et leur familles in 1978. The Florentine Geo-Spatial Archive seeks to follow the trajectory of Herlihy’s research and Litchfield’s digitization of the Catasto. Whereas the online Catasto is an invaluable searchable database of historical data, its application to other related archives is not direct. Our project seeks to deploy the most advanced digital technologies to create an open, robust platform where a range of data sets can be accessed and combined in new ways, and where researchers can incorporate their own projects and build upon the work of others. Instead of a series of online projects and discrete websites, such an archive would provide a single online gateway to some of the most innovative research being carried out on the city of Florence. We believe this approach could serve as an aggregator of historical knowledge that can be manipulated and combined into new kinds of knowledge not possible in individual projects. It would also expand the breadth and potential of Herlihy’s methodology and bring it into a productive dialogue with a broad cross section of approaches now being conducted on the city from many disciplinary fields.