Bede's Ecclesiastical History of England, ed. by A.M. Sellar, [1907], at sacred-texts.com
NOT long after, those monks also of the Scottish nation, who lived in the isle of Hii, with the other monasteries that were subject to them, were by the Lord’s doing brought to the canonical observance with regard to Easter, and the tonsure. For in the year of our Lord 716, when Osred was slain, and Coenred took upon him the government of the kingdom of the Northumbrians, the father and priest, Egbert, beloved of God, and worthy to be named with all honour, whom we have before often mentioned, came to them from Ireland, and was honourably and joyfully received. Being a most gracious teacher, and most devout in practising those things which he taught, and being willingly heard by all, by his pious and diligent exhortations, he converted them from that deep-rooted tradition of their fathers, of whom may be said those words of the Apostle, "That they had a zeal of God, but not according to knowledge." He taught them to celebrate the principal solemnity after the catholic and apostolic manner, as has been said, wearing on their heads the figure of an unending crown. It is manifest that this came to pass by a wonderful dispensation of the Divine goodness; to the end, that the same nation which had willingly, and without grudging, taken heed to impart to the English people that learning which it had in the knowledge of God, should afterwards, by means of the English nation, be brought, in those things which it had not, to a perfect rule of life. Even as, contrarywise, the Britons, who would not reveal to the English the knowledge which they had of the Christian faith, now, when the English people believe, and are in all points instructed in the rule of the Catholic faith, still persist in their errors, halting and turned aside from the true path, expose their heads without a crown, and keep the Feast of Christ apart from the fellowship of the Church of Christ.
The monks of Hii, at the teaching of Egbert, adopted the catholic manner of conversation, under Abbot Dunchad, about eighty years after they had sent Bishop Aidan to preach to the English nation. The man of God, Egbert, remained thirteen years in the aforesaid island, which he had thus consecrated to Christ, as it were, by a new ray of the grace of fellowship and peace in the Church; and in the year of our Lord 729, in which Easter was celebrated on the 24th of April, when he had celebrated the solemnity of the Mass, in memory of the Resurrection of our Lord, that same day he departed to the Lord and thus finished, or rather never ceases endlessly to celebrate, with our Lord, and the Apostles, and the other citizens of heaven, the joy of that greatest festival, which he had begun with the brethren, whom he had converted to the grace of unity. And it was a wonderful dispensation of the Divine Providence, that the venerable man passed from this world to the Father, not only at Easter, but also when Easter was celebrated on that day, on which it had never been wont to be celebrated in those parts. The brethren rejoiced in the sure and catholic knowledge of the time of Easter, and were glad in that their father, by whom they had been brought into the right way, passing hence to the Lord should plead for them. He also gave thanks that he had so long continued in the flesh, till he saw his hearers accept and keep with him as Easter that day which they had ever before avoided. Thus the most reverend father being assured of their amendment, rejoiced to see the day of the Lord, and he saw it and was glad.