This is one of the few surviving works of Cumianus, the Irish abbot, who lived during the height of Celtic monasticism in the 8th century. His work here relates directly to the question of Easter, namely its dating in relationship to the Latin calendar. This had become a point of friction with both the See of Canterbury and with the Papal Curia, which would come to a head in a few decades with the culmination of the Synod of Whitby.