A newly discovered Irish tract on the divisions of time in Laon, Bibliothèque Municipale, Ms. 422

This article provides the first study of the Irish computistica recently discovered in Laon, Bibliotheque Municipale, 422, a manuscript written in the first third of the ninth century in an undetermined scriptorium of Northern Francia. These materials, which display a strong interest in grammar and biblical exegesis in addition to compu-lus and also contain three words in Old Irish, were excerpted from an eighth-century Hiberno-Latin tract focussing especially on the divisions of time. The author of this work augmented considerably the contents of the early eighth-century Irish tract known as De divisionibus temporum (DDT), and for this reason the materials found in Laon 422 may be labelled a DDT auctus. Although aspects of this text's transmission remain unclear, it can be shown that an epitomised version of it has survived also in the famous manuscript Cologne, Dombibliothek, 83-11, completed at Cologne in AD 805. Moreover, the contents of this DDT auctus present significant parallels with Irish computistica now extant only in Breton manuscripts, suggesting that this text may have reached Carolingian Francia via Brittany, although the opposite route (from Northern Francia to Brittany, either directly or through Fleury) cannot be excluded.