How to find a medieval document when you only know the name of a city or a signatory? Bretaigne DAO opens its research notebook. Two manuscripts preserved in Rennes serve as a starting point. In Nantes, a reference to the second treaty of Guérande provides an initial lead to verify.
Two Manuscripts to Begin the Investigation
The Bibliothèque des Champs Libres holds, under the reference Ms 319, an old inventory of the titles of the Treasure of the Nantes castle. A second document, the alphabetical table Ms 320 dated 1773, assists in searching this collection by name, place, or subject. Together, these manuscripts allow us to trace how documents were described and classified at different times.
The next step is to link this with the archives currently preserved. It is necessary to note the folio and, when it appears in the inventory, the old reference number. One can then verify the connection using the date, names, and the subject of the act. The Archives of Loire-Atlantique mention another table in the history of their collection, established in 1758. We distinguish this reference from that of the Rennes manuscript dated 1773.
The Treaty of Guérande as a Research Case
For the second Treaty of Guérande from 1381, a study by Sébastien Damoiseaux cites a document preserved in Nantes in the Treasure of Charters, under the reference E 92-5. This indication provides a point of comparison. It remains to be verified whether the Rennes table mentions the treaty and, if so, to note the title and the folio that allow for searching the entry in the inventory. It is this process, with its steps and uncertainties, that we are making public in our documentary library.
In Tréguier, a Letter from Anne of Brittany and Two Readings of Its Date
A separate file shows why these verifications matter. The Archives of Côtes-d’Armor confirm that the thirteen letters from Anne to the bishop and the chapter of Tréguier are preserved under the reference 2 G 311, while the general directory lists them under 2 G 310. Several of these letters were published in the 19th century by Joachim Gaultier du Mottay.
The Archives provided us on November 6, 2026, with 26 views of the thirteen letters, recto and verso. Our library offers a PDF for consultation. It also presents both sides of a letter sent from Amboise in April 1498, in which Anne mentions the death of Charles VIII. On the verso, a pencil annotation gives the date as April 27, 1498. An educational sheet from the Archives provides the same date in the caption, while its transcription restores "XVIIe" in brackets. The date area on the recto shows a gap. We retain the month and year, and leave the day to be verified.
Sources and Reproductions
Our research notebook on charters
Notice of Tréguier, recto, verso, and download of the 26 views
Archives of Loire-Atlantique, presentation of the Treasure of Charters
Study by Sébastien Damoiseaux, note 60
Educational sheet from the Archives of Côtes-d’Armor
Illustration. Letter from Anne of Brittany to the chapter of Tréguier mentioning the death of Charles VIII. Departmental Archives of Côtes-d’Armor, 2 G 311, April 1498. Recto, view 5 of the file provided on November 6, 2026.
Conditions for reusing reproductions
Bretaigne DAO — BRETAGNE-DOC
Article prepared with the assistance of artificial intelligence tools. Source verification and editorial validation under the responsibility of Bretaigne DAO.
