Palladius, writing about the year 419 for the prefect Lausus, devotes one of the chapters of his book to a story that he heard from the desert fathers concerning a virgin in the sisterhood at Tabennesi, in the Thebaid of Egypt. The community had been founded as the women's house corresponding to the great monastery of Saint Pachomius, and it kept the same rule under an abbess of its own; in Palladius's day it numbered about four hundred sisters. They lived in cells and met for the offices in a common church; they laboured at weaving and at the kitchen; and they ate, when they ate, in silence at a common table, after the manner of the men's house across the river.

Among them, Palladius reports, was a sister who hid her ascetical labour under the mask of folly. The sisters called her σαλή, 'the fool,' and the Synaxarion of Constantinople gives her name as Isidora; Palladius gives no name. She wore on her head only a rag instead of the head-covering of the sisterhood, and so was reckoned among the lowest of the house and given the kitchen work.

Palladius describes the manner of her life in the house. She did not, he says, eat at the common table with the sisters; she lived on the crumbs that were swept up after the meals and on the wash-water of the pans she scoured. She was never seen to be at rest. She was never seen to take offence. She was reviled by every sister of the house, struck on the head, sneezed at, scolded, and made the target of every kind of contempt; and she received it all with no answer at all. Palladius adds, in the wording of his translator, that he himself could not say how a single soul had so borne, for so many years, what would have undone a strong body of men in a single day.

She had taken up, the chapter says, this discipline of folly deliberately and as a hidden ascesis: that as one ascetic in the desert flees the world for the love of God, this one had remained in the world but had flown from any honour she might receive. She fasted; she watched; she worked the labour of two; and she carried it under the appearance of being a creature half witted, so that no sister might love her and no soul reckon her among the consecrated.

There lived at this time in the desert of Porphyrites a great solitary, Abba Pitiroum, an old man much praised among the brethren for his asceticism. To him an angel of the Lord appeared, Palladius says, and said: 'Why do you think yourself reverend on the strength of these your virtues? Will you have me show you a woman more reverent than yourself? Go down to the women's house at Tabennesi, and there look for one who wears a διάδημα — a crown — on her head; she is greater than you.' The old man, who had not so much as seen a woman's house in many years, took the saying upon himself for an obedience and went down.

He came to the door of the monastery, the chapter goes on, and made his request to the abbess; the rule did not allow a man to enter, but for an anchorite of his reputation an exception was made. The abbess assembled all the sisters and brought them out before him one by one. He looked at every face and saw nothing. He asked, 'are these all?' She said, 'these are all.' He said, 'is there yet another?' She said, 'only the σαλή, the fool, in the kitchen; she does not come out.' He said, 'bring her.' They sent for her; she did not come; they went and fetched her by force.

When the sister was brought, Palladius says, the old man prostrated himself before her and said: 'Bless me, mother.' She prostrated herself in turn and said: 'Bless me, father.' All the sisters were astonished and said to him: 'Abba, do not be deceived; she is a fool.' He said to them: 'You are the deceived; she is amma to me and to you. I will pray that I may be found worthy of her on the day of judgement.' And he told them what had been said to him by the angel.

Then the sisters fell at her feet, every one of them, and confessed in tears the manner of their treatment of her; one had struck her, one had emptied dishwater over her, one had blown her nose in her food. They asked her forgiveness with every kind of word. Palladius reports nothing of her answer, only that she received the embraces of the sisters in silence.

Palladius closes the chapter with what he calls a strange and bitter ending. The fame of her sanctity could not be borne by her. She could not endure to be honoured in the place where she had been despised. A few days after the visit of Abba Pitiroum she went out of the monastery quietly, by night, and was not seen again. Whither she went, by what manner of life she lived after, in what country and on what day she fell asleep, Palladius says, no one knew. He himself, who set the story down, professed not to know.