Dúnchad (d. 717), 11th abbot of Iona, was of royal descent, being a direct descendant of some of the Uí Néill high-kings – grandson of Maél Cobo (d. 615) and grandnephew of Domnall (qv) (d. 642). Under his rule (from c.707) Iona, and possibly some of her daughter monasteries, first observed the Roman Easter term, having been persuaded (according to Bede) to do so by Ecgberht (qv): ‘the monks of Iona accepted the catholic ways of life under the teaching of Egbert while Dúnchad was abbot’ (Hist. ecc., v, 22). The Irish annals are in agreement with Bede on the date of this event (AU 715=716). The Annals of Tigernach (Tigernach Ua Bráein (qv)) also relate that in the following year, ‘the crown of tonsure was put upon the familia of Iona’ – i.e. the Roman form of tonsure was adopted.
Dúnchad seems to have held the abbacy for a time shortly after the death of Adomnán (qv), but may have been forced to withdraw in the face of opposition from his fellow Iona monks, who still clung to the old date for celebrating Easter and the Celtic tonsure. He may have regained the abbacy for a time in 717. A late twelfth-century scholium in the Martyrology of Óengus (qv) (fl. c.830) for Dúnchad's feast-day on 25 May states: ‘It was under him that the community of Iona accepted the lawful Easter.’ Apparently, not all of the Columban confederation conformed, however, if we are to judge from an entry for the following year in AU and Ann. Tig.: ‘the expulsion of the Columban familia from Pictland by King Nectan’.