Bede's Ecclesiastical History of England, ed. by A.M. Sellar, , at sacred-texts.com
NOT long after these events, Theodore, the archbishop, taking offence at some act of disobedience of Wynfrid, bishop of the Mercians,deposed him from his bishopric when he had held it but a few years, and in his, place ordained Sexwulf bishop,who was founder and abbot of the monastery which is called Medeshamstead,’ in the country of the Gyrwas.Wynfrid, thus deposed, returned to his monastery which is called Ad Barvae,and there ended his life in holy conversation.
Theodore then also appointed Earconwald bishop of the East Saxons, in the city of London, over whom at that time reigned Sebbi and Sighere, of whom mention has been made above.This Earconwald’s life and conversation, as well when he was bishop as before that time, is said to have been most holy, as is even now testified by heavenly miracles; for to this day, his horse-litter, in which he was wont to be carried when sick, is kept by his disciples, and continues to cure many of fevers and other ailments; and, not only sick persons who are laid under that litter, or close by it, are cured; but the very splinters cut from it, when carried to the sick, are wont immediately to bring healing to them.
This man, before he was made bishop, had built two famous monasteries, the one for himself, and the other for his sister Ethelburg, and established them both in regular discipline of the best kind. That for himself was in the district of Sudergeona, by the river Thames, at a place called Cerotaesei,that is, the Island of Cerot; that for his sister in the province of the East Saxons, at a place called In Berecingum, wherein she might be a mother and nurse of women devoted to God. Being put into the government of that monastery, she showed herself in all respects worthy of her brother the bishop, by her own holy life and by her regular and pious care of those under her rule, as was also manifested by heavenly miracles.