This academic blog outlines the project of reconstituting and describing the library of the Benedictine abbey of Saint-Martin at Sées (Orne, Normandy). The library’s collection is the last remaining important medieval collection in France still to be described. The history of the dispersal of the collection goes some way to explaining why. During the last years of the French Revolution, only nine manuscripts from Saint-Martin were incorporated into the collection of the Library of Alençon. The rest remained in Sées and were integrated, rather rapidly, into the Library of the Grand Séminare at Sées. In 1907, several volumes were moved to the Library of Alençon. At the end of the 1950s, 24 manuscripts from Saint-Martin, remaining in Sées since the Revolution, were discovered at the Bishopric at Sées.