Mid-19^th-century Venice: data available at the parish level show that overall mortality was far from evenly distributed in the city, with the death rates clearly following the social gradient of the different areas. First, we expect that there were spatial clusters where mortality risks were much higher than in other parts of the city. Second, we assume that such high-risk areas were themselves characterized by epidemiologic clusters, whereby some major diseases, associated with poor hygienic and socioeconomic conditions, reinforced each other operating in a synergistic way (syndemics). By carry out a more fine-grained analysis of mortality patterns and their distribution throughout the urban space, we will look for two kinds of clusters: spatial ones, identifying high-risk areas, and epidemiologic ones, exploring the relationships between different causes of death characterizing these spatial clusters.   A detailed study of mortality is made possible by an unusually rich dataset. The data include the conditions of dwellings (availability of water and sanitation) over the whole city, the causes of death with reported information on the address where people lived; daily temperatures, and weekly reports of food prices. All such data are included in a geographic information system (GIS) that uses contemporary digitized map.