A major Finnish research project “Constellations of Correspondence 2022-2025 (CoCo)” by the Finnish Literature Society (SKS), University of Helsinki, Helsinki Centre for Digital Humanities (HELDIG), and Aalto University, Department of Computer Science, has now been finalized, based on collections of 16 Finnish Cultural Heritage organizations, over 1600 fonds, and four earlier online critical editions of prominent Finns (A. Edelfelt, E. Lönnrot, J. V. Snellman, and Z. Topelius). The project’s major result is the new LetterSampo Finland portal https://kirjesampo.fi and its underlying Linked Open Data service https://www.ldf.fi/dataset/coco of about 1.3 million letters of the 19th century Grand Duchy of Finland era, including 116 000 related people and organizations – this is arguably the largest epistolary web service of its kind in the world.
A new long paper describing the vision, opportunities, and challenges of LetterSampo Finland, and its use for Digital Humanities research are now available as the pre-print below, to appear in the post-proceedings of the DHNB 2025 conference.
Eero Hyvönen, Petri Leskinen, Henna Poikkimäki, Heikki Rantala, Refael Leal, Jouni Tuominen, Senka Drobac, Ossi Koho, Ilona Pikkanen and Hanna-Leena Paloposki: Searching, exploring, and analyzing historical letters and the underlying networks: LetterSampo Finland – Finnish 19th-Century Letters on the Semantic Web. Digital Humanities in Nordic and Baltic Countries 2025 (DHNB 2025), post-proceedings, University of Oslo Library, Norway, September, 2025. In press.
https://seco.cs.aalto.fi/publications/2025/hyvonen-et-al-lettersampo-finland-2025.pdf
“Historical letters in archives are typically stored in fonds, based on letter recipients. To analyze the correspondences of a correspondent x, one has to aggregate the received letters in x’s own fond with the letters in the fonds of the correspondents y who have received letters from x. To address this challenge, epistolary data services have been created by aggregating data from distributed heterogeneous archival data silos and fonds. This paper presents an overview of a new in-use data service and portal for this task, LetterSampo Finland – Finnish Nineteenth-Century Letters on the Semantic Web. In contrast to various legacy services online, this system is based a Linked Open Data (LOD) Knowledge Graph (KG) in a SPARQL endpoint aggregated and harmonized from distributed heterogeneous data sources, in our case from 16 Finnish Cultural Heritage (CH) organizations and over 1600 fonds. The new massive KG contains metadata about nearly 1.3 million letters sent or received in the Grand Duchy of Finland during 1809-1917, including also letter contents from four critical editions of prominent Finns. The paper shows how this new KG and a portal on top of it can be used for searching and browsing letter data and for data analyzes in Digital Humanities (DH) research. We show how the aggregated datasets are related to and enrich each other, pin-pointing semantic challenges of data aggregation and linking processes needed. This kind of analysis is needed to make enriched LOD more transparent to the end user and to enhance data literacy for reliable computational analyzes.”
This research was funded by the Research Council of Finland (RCF). The open data, software tools, and web services are included in the national Finnish FIN-CLARIAH/DARIAH-FI research infrastructure funded by the RCF and the European Union Next GenerationEU program, using computational resources of CSC – IT Centre for Science.
More information about LetterSampo Finland and the CoCo project:
https://seco.cs.aalto.fi/projects/coco
Text: Eero Hyvönen / Image: https://kirjesampo.fi/