Bede's Ecclesiastical History of England, ed. by A.M. Sellar, , at sacred-texts.com
THE same Pope Honorius also wrote to the Scots, whom he had found to err in the observance of the holy Festival of Easter, as has been shown above, with subtlety of argument exhorting them not to think themselves, few as they were, and placed in the utmost borders of the earth, wiser than all the ancient and modern Churches of Christ, throughout the world; and not to celebrate a different Easter, contrary to the Paschal calculation and the decrees of all the bishops upon earth sitting in synod. Likewise John, who succeeded Severinus, successor to the same Honorius, being yet but Pope elect, sent to them letters of great authority and erudition for the purpose of correcting the same error; evidently showing, that Easter Sunday is to be found between the fifteenth of the moon and the twenty-first, as was approved in the Council of Nicaea He also in the same epistle admonished them to guard against the Pelagian heresy, and reject it, for he had been informed that it was again springing up among them. The beginning of the epistle was as follows:
To our most beloved and most holy Tomianus, Columbanus, Cromanus, Dinnaus, and Baithanus, bishops; to Cromanus, Ernianus, Laistranus, Scellanus, and Segenus, priests; to Saranus and the rest of the Scottish doctors and abbots, Hilarus, the arch-presbyter, and vice-gerent of the holy Apostolic See; John, the deacon, and elect in the name of God; likewise John, the chief of the notaries and vicegerent of the holy Apostolic See, and John, the servant of God, and counsellor of the same Apostolic See. The writings which were brought by the bearers to Pope Severinus, of holy memory, were left, when he departed from the light of this world, without an answer to the questions contained in them. Lest any obscurity should long remain undispelled in a matter of so great moment, we opened the same, and found that some in your province, endeavouring to revive a new heresy out of an old one, contrary to the orthodox faith, do through the darkness of their minds reject our Easter, when Christ was sacrificed; and contend that the same should be kept with the Hebrews on the fourteenth of the moon."
By this beginning of the epistle it evidently appears that this heresy arose among them in very late times, and that not all their nation, but only some of them, were involved in the same.
After having laid down the manner of keeping Easter, they add this concerning the Pelagians in the same epistle:
"And we have also learnt that the poison of the Pelagian heresy again springs up among you; we, therefore, exhort you, that you put away from your thoughts all such venomous and superstitious wickedness. For you cannot be ignorant how that execrable heresy has been condemned; for it has not only been abolished these two hundred years, but it is also daily condemned by us and buried under our perpetual ban; and we exhort you not to rake up the ashes of those whose weapons have been burnt. For who would not detest that insolent and impious assertion, 'That man can live without sin of his own free will, and not through the grace of God?' And in the first place, it is blasphemous folly to say that man is without sin, which none can be, but only the one Mediator between God and men, the Man Christ Jesus, Who was conceived and born without sin; for all other men, being born in original sin, are known to bear the mark of Adam's transgression, even whilst they are without actual sin, according to the saying of the prophet, 'For behold, I was conceived in iniquity; and in sin did my mother give birth to me.'