Universiteit Leiden

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Research project

Challenging the paradigm of filthy and unhealthy medieval towns

Mapping sanitary infrastructure in large urban societies in the Low Countries, 1200–1900

2016  -   2019
Roos van Oosten
NWO-Veni NWO-Veni

Heritage Leiden and Region, Team Archeologie Haarlem, Intergemeentelijke samenwerkingsverband Brughes and De Zwarte Doos Ghent


Earlier research by Van Oosten has demonstrated that in early modern urban societies medieval cesspits were replaced by sewers. Human excrement now drained directly into the canals and resulted in an unbearable ‘Great Stink’. This pattern is seen in Leiden and occurred a little later in other canal rich towns. This material shift suggests that the medieval concept of common good was abandoned and the needs of the few were given consideration over the needs of the many. These results challenge the long-held assumption that public health was an 18th- and 19th-century invention and that medieval towns were unorganized places of dirt, squalor and disease. These findings are in line with a revisionist school of thought in the history of public health that emphasizes that medieval town councils genuinely cared for the wellbeing of their town’s residents and wanted to ensure the common good or the body urban.

Artist’s impressions of pre-industrial Leiden. On the left: 15th century (cesspit era) On the right: 17th century (Great Stink era): the cesspits are replaced by sewers.

Research questions

The very first archaeological case studies of medieval sanitary infrastructure carried out in Leiden and Haarlem suggest that sanitation management deteriorated in postmedieval towns. In other words, medieval residents were better off in terms of public hygiene than postmedieval citizens. Whether this was the case in big medieval towns as well will be tested in two of the largest 14th-century boomtowns of northwestern Europe: Bruges, with 45,000 residents, and Ghent, with 64,000. How the trends in waste facilities and water supply facilities were interrelated will also be scrutinized further.


This project focuses on sanitary infrastructure (cesspits, sewers, wells, cisterns, water pipes) because the decisive factors in the health and wellbeing of residents of towns were access to clean water and the way in which fecal matter, the foremost pathogenic waste, was processed.

Four large, complex, urban societies have been selected for this Veni-funded project: Bruges, Ghent, Haarlem and Leiden. Data of exceptional quality resulting from archaeological excavations and from historical GIS-map application projects (Bruges-Map&House, and two pilot projects, Haarlem–DANS-KleineDataSubsidie2014 and Leiden–NWO-AlfaMeerwaarde2015) provide excellent groundwork for a systematic interdisciplinary (archaeological/historical/cartographic) and longitudinal (1200–1900) study.

Preliminary results

For preliminary results see the Leiden Medievalists Blog.