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Reviews: DECIMA

Two reviews of DECIMA, a project mapping 16th and 17th century Tuscany, directed by Nicholas Terpstra and Colin Rose

Published onJul 25, 2022
Reviews: DECIMA


Project Directors
Colin Rose, Brock University
Nicholas Terpstra, University of Toronto

Project URL

Project Reviewers
Review #1: Cristina Migliaccio, CUNY Medgar Evers College
Review #2: Diona Espinosa, University of Miami

Project Overview

Colin Rose

DECIMA is a historical geographic information system (HGIS) platform for spatial analysis of historical data from 16th- and 17th-century Tuscany. It maps databases created from contemporary manuscript sources onto two- and three-dimensional renderings of the early modern cities of Florence and Livorno. DECIMA consists of a series of interactive thematic maps hosted on its website and a sandbox-style GIS app allowing users to query, analyze, and visualize its datasets according to their own research needs. It is a member project of the Florentia Illustrata research consortium, organized under the aegis of the Harvard “Villa I Tatti” Centre for Italian Renaissance Studies.

The core visual sources for DECIMA are a 1584 map of Florence known as the Buonsignori map, after the cartographer Stefano Buonsignori. This map provides one of the best city-views of the 16th century and is remarkable in its detail and fidelity to local detail. Project researchers geo-referenced a high-resolution scan of this map provided by the Harvard Map Library. For Livorno, researchers at the University of Florence created a digital 3D model from a physical 3D model of the 18th century, itself built in the 1990s from a set of city plans conserved in the Archivio di Stato di Livorno.

The core datasets of the DECIMA are a series of population and tax censuses from Tuscany in the 16th and 17th centuries. For Florence, these include tax assessments (an estimo and a decima) from 1551 and 1561, as well as a population census taken in the wake of an epidemic of bubonic plague in 1632. For Livorno, a series of arroti and portate from 1642 provide a view of that city’s urban development in the 17th century. Combining these datasets into a large relational database allows for analysis of household size, occupational structures, property values, household wealth, gender makeup of populations, and other pertinent variables. These datasets are supplemented on an idiosyncratic basis when new and interesting documents appear or when researcher interest turns to new questions; for instance, co-director Colin Rose is currently engaged in a project to map the investigation and surveillance activity of Florentine police forces against the socioeconomic data contained in the 1561 decima dataset.

Teams of graduate researchers consisting of MA and PhD students at the University of Toronto created these databases from digitized manuscript sources. These teams have evolved in the 10 years of the project’s life, but have generally consisted of 3-5 data researchers at a given time, supplemented by the project directors, a post-doc, and various PhD researchers fulfilling ad hoc roles within the project such as web design, 3D modeling, and communications.

The project primarily targets academic audiences as both a research and pedagogical tool. Its front-end website contains ready-made maps and lesson plans for inclusion in undergraduate classrooms. Its back-end databases and GIS app allow researchers to query and analyze data according to their own research questions, building queries across some fifty fields of nominal, economic, prosopographic, and locational data.

DECIMA has received funding from the Social Sciences and Humanities Research Council of Canada: a standard research grant in 2010, an Insight Grant in 2015, an Insight Grant in 2019, and an Insight Development Grant in 2020. It has participated in various student-engagement grants over the years including the University of Toronto’s STEP Forward program. Its post-doctorate program has been largely funded by the University of Toronto’s Faculty of Arts and Social Science as well as the AHRC and University of Exeter.

Project Review #1

Cristina Migliaccio

DECIMA (Digitally Encoded Census Information & Mapping Archive) is a digital humanities project that examines three moments in Florentine history through locational information and census data. Its website illustrates the cartography of Florence during 1551, 1561, and 1632 and corresponding census data from those years. The DECIMA project takes its name from the 1561 decima tax, a 10% property value tax that allowed the second duke of Florence to account for his population’s assets.

As a dynamic digital tool for exploring Florence, known as the jewel of the Italian renaissance, during the infamous Medici reign, DECIMA supports research at the intersections of geography, society, and commerce. Detailed census data for the three years was derived by the DECIMA team from the Archivio di Stato di Firenze and the Biblioteca Nazionale-Centrale Firenze and delicately converted to modern, searchable database technology, with scrupulous attention to preserving the integrity of its original scribes’ orthography.

Though historian Caroline Callard asserts that “Until the mid-seventeenth century, Tuscany had a prudent tradition of censoring official writings” (249), the DECIMA team explains that Florentine governments of the 16th and 17th centuries were obsessive data collectors and kept detailed records about the people who lived in Florence. The 1551 and 1632 data sets represent demographic information such as population figures, names of owners, residents, and tenants living in the city at the time. They also reflect spatial data that delineates quarters and streets where households resided. The 1561 data set is more expansive, reflecting economic information such as the taxable value of the immobile properties, revenue derived from rent-listed property, and how each property was contractually disposed (e.g., leased or rented).

DECIMA was first created in 2011 and went live in 2014. Originally conceived of as a tool for cultural historians, the project was born of University of Toronto historian Nicholas Terpstra’s fascination with the “[the] rich spatial descriptors and socioeconomic data” (Rose) of the 1561 census document. Creating a geo-map using those descriptors was the initial premise for DECIMA. Terpstra and his co-investigator Colin Rose refined their methods as iterations of the project evolved to introduce other data into DECIMA.

The first major research output of the project is the 2016 Routledge publication Mapping Space, Sense, and Movement in Florence: Historical GIS and the Early Modern City, which comprises three parts: essays about DECIMA, research projects deploying DECIMA, and related spatial histories. A series of articles and other texts related to the project was published by Terpstra and other authors between 2015 and 2020. Early interest in the DECIMA Project emerged from art historians and has since exploded due to its value as a pedagogical tool alongside partner research projects.

The core of the DECIMA project is a WebGIS App (and many of the sub-maps created by co-researchers, colleagues, and others) which began as a FileMaker database and was transformed into a user-friendly interactive web map using ArcGIS Online software. Though the app is not a mobile app, it works on a mobile device as well.

DECIMA has many user-friendly features that answer questions and encourage humanistic research. One is an Italian-to-English glossary compiled from the Grande Dizionario della Lingua Italiana to facilitate understanding of street names, occupations, shops and property, and currency and wages encountered by users. The DECIMA Interface Quick Guide is another thoughtful feature that helps users search, navigate, and repurpose data on the map.

Perhaps the most exciting aspect of the DECIMA project is its interactive and collaborative potential. Using the search features listed above, researchers can develop their own inquiries and find new ways of answering them. The site showcases a series of intriguing thematic sub-map projects that center on cultural recovery, such as the one entitled “On the Eve of the Ghetto,” a map of Jewish residences around the city that reflects the 1568 ordering of the city’s Jews by the Medici duke, before the creation of the the city’s ghetto in 1570.

Another thematic sub-map, “Sex and the Sacred,” plots the known residences of sex workers against the streets where the practice of their trade was permitted. These and partner projects like “Accessing Anna” which recreates 1749 soundscapes from a Jewish woman’s diary account of her enforced committal to Roman Casa dei Catecumeni (a Catholic conversion house), illustrate the demand for enlarging this study to include other periods and subjects in Florentine history and bring Florence to light in new and exciting ways for scholars, pedagogues, and students.

Crystal Hall points out that both digital humanities and Italian studies “have struggled with inclusivity and the representation for traditionally marginalized voices… [though] both fields offer tools and materials of study that can assist in [a] transformation” (103). In its combination of geo-mapping and careful digitization of archival census data, DECIMA creates new ontologies for socio-cultural recovery of previously ignored Florentine history, particularly that of marginalized people of the time period. DECIMA also responds to scholar Domenico Fiormonte’s 2016 call for non-Anglophone digital humanities informed by Italian studies. As an emerging scholar in both fields, I am thrilled by the model of inquiry DECIMA offers and, more importantly, by the potential a project like this one has for the recovery that might be possible from other data driven histories, especially for parts of Italy historically undermined in the cultural record.

Works Cited

Callard, Caroline. “Diplomacy and Scribal Culture: Venice and Florence, Two Cultures of Political Writings.” Italian Studies, vol. 66, no. 2, Taylor & Francis, 2011, pp. 249–62. DECIMA - The Digitally Encoded Census Information and Mapping Archive. d99cf7c398552ca39. Accessed 12 November 2021.

Fiormonte, Domenico. “Towards a Cultural Critique of the Digital Humanities.” Historical Social Research/Historische Sozialforschung, 2012, pp. 59–76.

Hall, Crystal. Digital Humanities and Italian Studies: Intersections and Oppositions. Taylor & Francis, 2019.

Padgett, John F., and Christopher K. Ansell. “Robust Action and the Rise of the Medici, 1400-1434.” American Journal of Sociology, vol. 98, no. 6, 1993, pp. 1259–319.

Rose, Colin. Personal Interview. 14 November 2021.

Terpstra, Nicholas, and Colin Rose, eds. Mapping Space, Sense, and Movement in Florence: Historical GIS and the Early Modern City. 1st edition, Routledge, 2019.

Project Review #2

Diana Espinoza

DECIMA provides searchable access to three different kinds of censuses in Florence from 1551, 1561, and 1632: one focused on the description of the city, the second on property tax, and the third on the surviving population after the plague of 1630. DECIMA offers a new way to understand Florentine history by focusing on its people through digital mapping. Scholars and other researchers interested in this project can navigate this map street-by-street, house-by-house, and person-by-person. Search options include individuals, institutions, churches, names, among others.

The project’s use of the map drawn by the Italian Olivetan monk and cartographer Buonsignori emphasizes how the city looked during that period, such as the divisions by quartiers and proximity of houses. Every red point on the map represents a documented property in the censuses and, with just one click, provides access to detailed, interpretative, and descriptive annotations, including names of residents, owner, gender, and rent value.

The project also provides useful secondary source materials like a glossary of terms to assist users with digital GIS wayfinding. The glossary was compiled from the Grande Dizionario della Lingua Italiana (GDLI), the preeminent historical dictionary of the Italian language, and incorporates terms, concepts, and place names, as well as translation. While some street names in Florence correspond to their 16th-century counterparts, many have changed as a result of urban planning. The glossary, therefore, helps users locate their modern equivalents. For every term, Italian etymologies are also included. Most notable in the glossary is its currency and wages segment, which provides estimation of the taxable values of properties, rents, and documents of the censuses. The discussion of currencies — scudo (a gold currency), lira (silver currency), and the soldo and their conversions — provides valuable information related to the 16th- and 17th-century economies in Florence.

DECIMA does not provide a corpus of images of that Florentine Epoque or copies of the manuscripts that the team used for compiling all the information. However, it includes some of the earliest documents within two videos to situate the experience of contemporary scholars, readers, and users. One looks at Piazza della Signoria and the other one at Piazza del Duomo, and both offer a reconstruction of the medieval streetscape using contemporary locations as a reference. These compilation videos incorporate period music along with historical images and current photos of Florence. They offer key information to accompany the map.

DECIMA has done remarkable work providing virtual access to geographically dispersed materials, now compiled, and digitized. The project is a useful teaching tool that facilitates engagement with the social and economic world of 16th- and 17th-century Florence and includes a collection of teaching resources. DECIMA is thus a promising project with great potential to continue innovating the study of Florence’s history.


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