Bede's Ecclesiastical History of England, ed. by A.M. Sellar, [1907], at sacred-texts.com
AT that time the venerable servant of Christ, and priest, Egbert, who is to be named with all honour, and who, as was said before, lived as a stranger and pilgrim in Ireland to obtain hereafter a country in heaven, purposed in his mind to profit many, taking upon him the work of an apostle, and, by preaching the Gospel, to bring the Word of God to some of those nations that had not yet heard it; many of which tribes he knew to be in Germany, from whom the Angles or Saxons, who now inhabit Britain, are known to have derived their race and origin; for which reason they are still corruptly called "Garmans" by the neighbouring nation of the Britons. Such are the Frisians, the Rugini, the Danes, the Huns, the Old Saxons, and the Boructuari. There are also in the same parts many other peoples still enslaved to pagan rites, to whom the aforesaid soldier of Christ determined to go, sailing round Britain, if haply he could deliver any of them from Satan, and bring them to Christ; or if this might not be, he was minded to go to Rome, to see and adore the thresholds of the holy Apostles and martyrs of Christ.
But a revelation from Heaven and the working of God prevented him from achieving either of these enterprises; for when he had made choice of most courageous companions, fit to preach the Word, inasmuch as they were renowned for their good deeds and their learning, and when all things necessary were provided for the voyage, there came to him on a certain day early in the morning one of the brethren, who had been a disciple of the priest, Boisil, beloved of God, and had ministered to him in Britain, when the said Boisil was provost of the monastery of Mailros, under the Abbot Eata, as has been said above. This brother told him a vision which he had seen that night. "When after matins," said he, "I had laid me down in my bed, and was fallen into a light slumber, Boisil, that was sometime my master and brought me up in all love, appeared to me, and asked, whether I knew him? I said, ‘Yes, you are Boisil.’ He answered, ‘I am come to bring Egbert a message from our Lord and Saviour, which must nevertheless be delivered to him by you. Tell him, therefore, that he cannot perform the journey he has undertaken; for it is the will of God that he should rather go to teach the monasteries of Columba.’ Now Columba was the first teacher of the Christian faith to the Picts beyond the mountains northward, and the first founder of the monastery in the island of Hii, which was for a long time much honoured by many tribes of the Scots and Picts. The said Columba is now by some called Columcille, the name being compounded from "Columba" and "Cella." Egbert, having heard the words of the vision, charged the brother that had told it him, not to tell it to any other, lest haply it should be a lying vision. But when he considered the matter secretly with himself, he apprehended that it was true, yet would not desist from preparing for his voyage which he purposed to make to teach those nations.
A few days after the aforesaid brother came again to him, saying that Boisil had that night again appeared to him in a vision after matins, and said, "Why did you tell Egbert so negligently and after so lukewarm a manner that which I enjoined upon you to say? Yet, go now and tell him, that whether he will or no, he must go to Columba’s monasteries, because their ploughs are not driven straight; and he must bring them back into the right way." Hearing this, Egbert again charged the brother not to reveal the same to any man. Though now assured of the vision, he nevertheless attempted to set forth upon his intended voyage with the brethren. When they had put aboard all that was requisite for so long a voyage, and had waited some days for fair winds, there arose one night so violent a storm, that part of what was on board was lost, and the ship itself was left lying on its side in the sea. Nevertheless, all that belonged to Egbert and his companions was saved. Then he, saying, in the words of the prophet, "For my sake this great tempest is upon you,"’ withdrew himself from that undertaking and was content to remain at home.
But one of his companions, called Wictbert, notable for his contempt of the world and for his learning and knowledge, for he had lived many years as a stranger and pilgrim in Ireland, leading a hermit’s life in great perfection, took ship, and arriving in Frisland, preached the Word of salvation for the space of two whole years to that nation and to its king, Rathbed; but reaped no fruit of all his great labour among his barbarous hearers. Returning then to the chosen place of his pilgrimage, he gave himself up to the Lord in his wonted life of silence, and since he could not be profitable to strangers by teaching them the faith, he took care to be the more profitable to his own people by the example of his virtue.