On this day, 24 April 729, Easter was celebrated at Iona for the first time according to the reckoning established by the Council of Nicea in 325 AD.
Iona and the various monasteries of the paruchia of Saint Columba had resisted the Nicean ruling for 400 years, such was the stubborn Irish adherence to their older tradition which they believed had come to them from Saint John the Beloved!
A map of monastic Ireland in 650 AD showing the Columban monasteries
http://www.wesleyjohnston.com/users/ireland/maps/historical/map650.gif A brief life of Saint Egbert of Iona who laboured to bring Iona into line with the Christian world and died on the very day, 24 April 729, when Iona celebrated Easter for the first time with the rest of the Church.
http://groups.yahoo.com/group/celt-saints/message/4177