Bede's Ecclesiastical History of England, ed. by A.M. Sellar, , at sacred-texts.com
WHEN the man of God, Egbert, perceived that neither he himself was permitted to go and preach to the nations, being withheld for the sake of some other advantage to the holy Church, whereof he had been forewarned by a revelation; nor that Wictbert, when he went into those parts, had availed to do anything; he nevertheless still attempted to send holy and industrious men to the work of the Word, among whom the most notable was Wilbrord, a man eminent for his merit and rank as priest. They arrived there, twelve in number, and turning aside to Pippin, duke of the Franks, were gladly received by him; and as he had lately subdued the nearer part of Frisland, and expelled King Rathbed, he sent them thither to preach, supporting them at the same time with his sovereign authority, that none might molest them in their preaching, and bestowing many favours on those who consented to receive the faith. Thus it came to pass, that with the help of the Divine grace, in a short time they converted many from idolatry to the faith of Christ.
Following their example, two other priests of the English nation, who had long lived as strangers in Ireland, for the sake of the eternal country, went into the province of the Old Saxons, if haply they could there win any to Christ by their preaching. They were alike in name as in devotion, Hewald being the name of both, with this distinction, that, on account of the different colour of their hair, the one was called Black Hewald and the other White Hewald. They were both full of religious piety, but Black Hewald was the more learned of the two in Scripture. When they came into the province, these men took up their lodging in the guesthouse of a certain township-reeve, and asked of him that he would conduct them to the ealdorman who was over him, for that they had a message concerning matters of importance to communicate to him. For those Old Saxons have no king, but many ealdormen set over their nation; and when any war is on the point of breaking out, they cast lots indifferently, and on whomsoever the lot falls, him they all follow and obey during the time of war; but as soon as the war is ended, all those ealdormen are again equal in power. So the reeve received and entertained them in his house some days, promising to send them to the ealdorman who was over him, as they desired.
But when the barbarians perceived that they were of another religion,—for they continually gave themselves to singing of psalms and prayer, and daily offered up to God the Sacrifice of the saving Victim, having with them sacred vessels and a consecrated table for an altar,— they began to grow suspicious of them, lest if they should come into the presence of their ealdorman, and converse with him, they should turn his heart from their gods, and convert him to the new religion of the Christian faith; and thus by degrees all their province should be forced to change its old worship for a new. Wherefore on a sudden they laid hold of them and put them to death; and White Hewald they slew outright with the sword; but they put Black Hewald to lingering torture and tore him limb from limb in horrible fashion, and they threw their bodies into the Rhine. The ealdorman, whom they had desired to see, hearing of it, was very angry that strangers who desired to come to him had not been suffered to come; and therefore he sent and put to death all those villagers and burned their village. The aforesaid priests and servants of Christ suffered on the 3rd of October.
Miracles from Heaven were not lacking at their martyrdom. For their dead bodies, having been cast into the river by the pagans, as has been said, were carried against the stream for the space of almost forty miles, to the place where their companions were. Moreover, a long ray of light, reaching up to heaven, shone every night above them wheresoever they chanced to be, and that too in the sight of the very pagans that had slain them. Moreover, one of them appeared in a vision by night to one of his companions, whose name was Tilmon, a man of renown and of noble birth in this world, who having been a thegn had become a monk, telling him that he might find their bodies in that place, where he should see rays of light reaching from heaven to the earth. And so it befell; and their bodies being found, were buried with the honour due to martyrs; and the day of their passion or of the finding of their bodies, is celebrated in those parts with fitting veneration. Finally, Pippin, the most glorious duke of the Franks, learning these things, caused the bodies to be brought to him, and buried them with much honour in the church of the city of Cologne, on the Rhine. And it is said that a spring burst forth in the place where they were killed, which to this day affords a plentiful stream in that same place.