The silent sisters is an order of women belonging to the Faith of the Seven. They are sworn to the service of the Stranger and have taken vows of chastity and silence. The silent sisters attend to the dead. They are not to be confused with septas.
Silent sisters are sometimes referred to as the Stranger's wives or death's handmaidens. They are shrouded in grey and keep their faces cowled except for their eyes. It is said that theirs is a serene life, a life of prayer and contemplation and good works. They bring solace to the living and peace to the dead.
Girls and women are sometimes sent to become silent sisters as a punishment. It is said that the silent sisters are always glad to welcome widows. People of Westeros are uneasy about and wary of the silent sisters. The silent sisters prepare men for the grave, and it is considered ill fortune to look on the face of death. The belief that their tongues are removed is a myth; silent sisters are silent because of piety.
One of the silent sisters' main functions is the collection and handling of the bodies of the dead, preparing them for funerals. More frequently flesh is stripped from a deceased's bones with beetles or boiling. Sometimes the sisters remove the bowels and organs and drain a body of blood, stuffing it with salts and fragrant herbs.
Alysanne Osgrey was sent to the order because her father, Ser Eustace, rebelled during the First Blackfyre Rebellion. During the Great Spring Sickness nearly all of the silent sisters in King's Landing died of the plague.
A Game of Thrones
A Clash of Kings
Silent sisters present Eddard Stark's bones to Catelyn Stark at Riverrun, as arranged by Tyrion Lannister. Catelyn requests the silent sisters to take Eddard's bones to Winterfell so that he may be buried in the crypt beneath the castle in accordance with the tradition of House Stark. They are to be escorted by Hal Mollen.
A Storm of Swords
A Feast for Crows
Travelling to Duskendale, Brienne of Tarth comes across a band of silent sisters. She asks them if they have seen her sister but they shake their heads. Later Brienne, Ser Illifer, and Ser Creighton Longbough come across some poor fellows marching to King's Landing, who tell them that even silent sisters have been molested.
During Ser Jaime Lannister's vigil over his father's Tywin's body the silent sisters come single file down the Stranger's Steps of the Great Sept of Baelor. They and the other devout make a circuit of the sept, worshipping at each of the seven altars to honor the seven aspects of the deity. To each god they make a sacrifice and sing a hymn.  When the funeral procession departs King's Landing six silent sisters ride attendance on Tywin's bones. At Riverrun Jaime dreams of a woman all in grey, a silent sister. A hood and veil conceal her features but he can see the candles burning in the green pools of her eyes; it is his mother, Joanna Lannister.
Cersei Lannister suggests to Falyse Stokeworth that she join the silent sisters after Bronn ordered her gone from Stokeworth. Cersei then thinks of a better way to get rid of her and gives Falyse to Qyburn. During Cersei's imprisonment three silent sisters hold her down as Septa Scolera strips her bare.
A Dance with Dragons
In Meereen Ser Barristan Selmy considers what is to be done with Quentyn Martell's body. He thinks that the silent sisters would have seen to it at home, but this is Slaver's Bay and the nearest silent sister is 10,000 leagues away.
Wylla, every time you open your mouth you make me want to send you to the silent sisters.
If I had any sense I'd give you to the silent sisters. They cut the tongues out of girls who talk too much.
Podrick: The silent sisters never speak. I heard they don't have tongues.
Meribald: Mothers have been cowing their daughters with that tale since I was your age. There was no truth to it then and there is none now. A vow of silence is an act of contrition, a sacrifice by which we prove our devotion to the Seven Above.
- A Dance with Dragons, Chapter 65, Cersei II.
- A Feast for Crows, Chapter 4, Brienne I.
- A Feast for Crows, Chapter 8, Jaime I.
- A Clash of Kings, Chapter 39, Catelyn V.
- A Feast for Crows, Chapter 32, Cersei VII.
- The Sworn Sword.
- A Game of Thrones, Chapter 30, Eddard VII.
- Fire & Blood, Under the Regents - The Hooded Hand.
- A Feast for Crows, Chapter 17, Cersei IV.
- The World of Ice & Fire, The Vale.
- So Spake Martin: Private Meeting (Santa Fe, NM), May 04, 2004
- The World of Ice & Fire: The Westerlands (unabridged). georgerrmartin.com
- A Feast for Crows, Chapter 41, Alayne II.
- A Clash of Kings, Chapter 30, Arya VII.
- A Storm of Swords, Chapter 65, Arya XII.
- A Feast for Crows, Chapter 28, Cersei VI.
- A Feast for Crows, Chapter 16, Jaime II.
- A Feast for Crows, Chapter 44, Jaime VII.
- A Feast for Crows, Chapter 43, Cersei X.
- A Dance with Dragons, Chapter 19, Davos III.
- A Dance with Dragons, Chapter 33, Tyrion VIII.
- A Dance with Dragons, Chapter 70, The Queen's Hand.
- A Feast for Crows, Chapter 31, Brienne VI.