Noémie Lacroix, Jean-Paul Rehr, Leif Scheuermann Fairs in History: the public database of the CoMOR project Throughout the high to late Middle Ages and up to the modern period, fairs played an important role in the development of the European economy and espe- cially in the trans-regional exchange of goods. In order to understand the radical expansion of money markets and the transformation of exchange that occurred in the late Middle Ages and the first centuries of the early modern period that made the role of fairs so important in the economy, the CoMOR project focuses on the period between the decline of the classic fairs at Champagne beginning around 1350 and the emergence of fairs dedicated to finance and money exchange in the seventeenth century, with a particular emphasis on the fairs of France, Ger- many, and the north of Italy. Funded by the French Agence nationale de la re- cherche and its German equivalent, the Deutsche Forschungsgemeinschaft, the principal investigators Jean-Louis Gaulin and Susanne Rau made an online, col- laborative database to record and support the research central to the project. This database needed to respond to the goals of the project and its various con- tributors, as well as providing a platform for future collaboration. This article presents the database—hosted at http://fairs-in-history.huma-num.fr— together with the decisions taken to respond to the project, the contributor requirements, and the opportunities that it offers to users. 1 The requirements of the CoMOR project The multidisciplinary quality of the project team quickly led to the question of each team member’s particular requirements for the database, with respect to both subject area and methods. Indeed, the long history of European fairs be- tween 1350 and 1600 is one so rich that it can be approached in numerous ways, with numerous methods, as evidenced by the articles in the current volume.  For a technical explanation of the workings of the database, including how the project assures the long-term viability of its data, see the Data Management Plan of the project in Jean-Paul Rehr, Jean-Louis Gaulin, Susanne Rau, Ulf Christian Ewert. The CoMOR Data Management Plan. 2019–2023. DOI: 10.34847/nkl.8ceekn2a. See also the forthcoming data paper by the same authors with Leif Scheuermann. The CoMOR project would also like to recognize and thank Marjorie Burghart for her early contributions to the digital conceptualization of the project. Open Access. © 2025 the author(s), published by De Gruyter. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. https://doi.org/10.1515/9783111621296-018