Adomnán, plague and the Easter controversy

Adomnán's description (Vita Columbae II.46) of how the intercession of St. Columba preserved the Picts and the Irish in Britain alone among the peoples of western Europe against two great epidemics of bubonic plague is a coded defence of their use of the traditional Irish 84-year Easter table against the Dionysian Easter table as used throughout the rest of western Europe. His implication is that God sent the plagues to punish those who used the Dionysian table. Hence Adomnán still adhered to the 84-year table by the time that he composed the Vita Columbae c. 697. It probably took a third epidemic 700-c. 702 to persuade Adomnán that his interpretation of the earlier epidemics was incorrect, so that Bede (HE V.15) is correct to date his conversion to the Dionysian table to a third visit to Northumbria c. 702.