The Royal Irish Academy manuscript known by its shelfmark ‘23 N 10’ was produced in Ballycummin, Co. Roscommon, in the sixteenth century. It is an extraordinarily important manuscript for many reasons, but it is particularly significant because it contains tales which are amongst the oldest surviving literature in Irish. These tales would originally would have been preserved in a now-lost manuscript called Cín Dromma Snechta. Aside from wonderful examples of Old Irish narrative literature, the manuscript also preserves legal texts, poetry and wisdom literature from early medieval Ireland. This two-day conference will explore all aspects of the production, survival and significance of the ‘Book of Ballycummin’ and the marvels of medieval Irish literature which are contained within it. Described in the nineteenth century as a ‘little remnant of the work of the ancients’, this manuscript is a remarkable witness to the earliest development of Irish literature.