Bede's Ecclesiastical History of England, ed. by A.M. Sellar, , at sacred-texts.com
NOT long after, news was brought from the same island, that certain persons were again attempting to teach and spread abroad the Pelagian heresy, and again the holy Germanus was entreated by all the priests, that he would defend the cause of God, which he had before maintained. He speedily complied with their request; and taking with him Severus, a man of singular sanctity, who was disciple to the blessed father, Lupus, bishop of Troyes, and at that time, having been ordained bishop of the Treveri, was preaching the Word of God to the tribes of Upper Germany, put to sea, and with favouring winds and calm waters sailed to Britain.
In the meantime, the evil spirits, speeding through the whole island, were constrained against their will to foretell that Germanus was coming, insomuch, that one Elafius, a chief of that region, without tidings from any visible messenger, hastened to meet the holy men, carrying with him his son, who in the very flower of his youth laboured under a grievous infirmity; for the sinews of the knee were wasted and shrunk, so that the withered limb was denied the power to walk. All the country followed this Elafius. The bishops arrived, and were met by the ignorant multitude, whom they blessed, and preached the Word of God to them. They found the people constant in the faith as they had left them; and learning that but few had gone astray, they sought out the authors of the evil and condemned them. Then suddenly Elafius cast himself at the feet of the bishops, presenting his son, whose distress was visible and needed no words to express it. All were grieved, but especially the bishops, who, filled with pity, invoked the mercy of God; and straightway the blessed Germanus, causing the youth to sit down, touched the bent and feeble knee and passed his healing hand over all the diseased part. At once health was restored by the power of his touch, the withered limb regained its vigour, the sinews resumed their task, and the youth was, in the presence of all the people, delivered whole to his father. The multitude was amazed at the miracle, and the Catholic faith was firmly established in the hearts of all; after which, they were, in a sermon, exhorted to amend their error. By the judgement of all, the exponents of the heresy, who had been banished from the island, were brought before the bishops, to be conveyed into the continent, that the country might be rid of them, and they corrected of their errors. So it came to pass that the faith in those parts continued long after pure and untainted. Thus when they had settled all things, the blessed prelates returned home as prosperously as they had come.
But Germanus, after this, went to Ravenna to intercede for the tranquillity of the Armoricans, where, after being very honourably received by Valentinian and his mother, Placidia, he departed hence to Christ; his body was conveyed to his own city with a splendid retinue, and mighty works attended his passage to the grave. Not long after, Valentinian was murdered by the followers of Aetius, the patrician, whom he had put to death, in the sixth year of the reign of Marcian, and with him ended the empire of the West.