Bullinger Digital

Heinrich Bullinger (1504–1575) was a collaborator and successor of Huldrich Zwingli and an important multiplier for the ideas of the Reformation in Switzerland and Europe. From his extensive correspondence, some 2000 letters that Bullinger wrote and 10,000 letters that he received have been preserved. The originals are kept in the Zurich State Archives and the Zurich Central Library. 80% of the letters are in Latin, most of the others in Early New High German. The Bullinger Digital project was based on the data compiled by the Swiss Reformation Studies Institute (IRG). These include the metadata for the entire correspondence, 3,100 letters that have already been edited and provisional transcriptions of a further 5,400 letters.

Project Aims Bullinger Digital (2021–2023) 

In the first phase of the project, the aim was to make the entire correspondence available online. In a first step, the metadata existing on index cards was digitized and transferred into a database with the help of the interested public (Citizen Science campaign). In a second step, we enriched the database with the existing transcriptions, the scholarly commentaries from the HBBW edition and the facsimiles of the letters created specifically for the project. In addition, we trained handwriting recognition systems (HTR) based on scan-aligned transcriptions in order to efficiently convert the remaining 3,500 letters into electronic text. We also trained a machine translation system to translate the letters written in Early Modern Latin into modern German and developed a model to normalize the letters written in Early Modern High German. The machine translations of the letter texts are available on GitHub. Finally, we have made the results of this work available to the research community and the interested public in a specially developed online search system.

Project Aims Bullinger Digital 2.0 (2024–2025)

In the follow-up project Bullinger Digital 2.0, we transfered the data from the first project phase into a TEI XML corpus and our own online search system to the TEI Publisher. The transition to the TEI Publisher guarantees the long-term availability of the online search system, which will continue to be maintained by the State Archives of the Canton of Zurich after the end of the project. To meet the international interest in the Bullinger correspondence, we also added an English version of the user interface. 

In addition, we have enriched the corpus with automatically extracted keywords, improved the automatic named entity recognition (NER), and had it reviewed/corrected in another Citizen Science campaign. We have also expanded the linking of the Bullinger correspondence with other knowledge resources and digital editions. Finally, we have translated all registers and manually transcribed letter texts into English using LLMs and stored them on GitHub. You can also find the documentation for models and tools on GitHub.

Technical Tools 

• Database / online search system (Bullinger Digital): SQLite, Python, Cantaloupe IIIF-Server, Elasticsearch, React (NextJS)
• Database / online search system (2nd phase): TEI Publisher
• Automatic handwriting recognition: HTR-Flor, Transkribus, TrOCR
• Machine translation (Bullinger Digital): Sockeye, Classical Language Toolkit 
• Machine translation (2nd phase): GPT4o
• Self-developed programs for language identification (Latin vs. Early New High German) and recognition of code-switching
• App developed in-house for assigning scans
• CMS for the manual correction of metadata: Directus
• "Mithelfen" tool (in-house development) for the Citzen Science campaign for named entity recognition and linking: NextJS und PostgreSQL; Quellcode auf GitHub
• XML-Editor Oxygen
• GitHub for version control and downloading 
• Trello for project management

Project Duration

Bullinger Digital: January 2021 – May 2023
Bullinger Digital 2.0: January 2024 – June 2025

Further information 
Project webpage (in German)