There is a common motif in myth of three women who determine fate. The Graeae of Greece known as “the grey ones”; the Moirai of Greece, or the Parcae or fates, the Roman evolution into the personification of destiny, past present and future; and the Norse Norns who ruled the destinies of gods and men watering the world tree Yggdrasill from the Well of Urdr (Well of Fate); and the Irish Morrigan, often described as a trio of individuals, all sisters, called "the three Morrígna".
I would suggest that there are three crones in Westeros who generally fit with these descriptions.
The Graeae were daughters of the sea-deities Phorcys and Ceto (from which their name the Phorcydes derived), and sisters to the Gorgons. The Graeae took the form of old, grey-haired women. Their age was so great that a human childhood for them was hardly conceivable. the "well-clad" Pemphredo (Πεμφρηδώ "alarm") and the "saffron-robed" Enyo (Ἐνυώ "horror" the "waster of cities" who also had an identity separate from this sisterhood) and Deino (Δεινώ "dread", the dreadful anticipation of horror). They shared one eye and one tooth, which they took turns using and were beings on whom no ray of sun ever looks down, nor moon at night. By stealing their eye while they were passing it among themselves, the hero Perseus forced them to tell the whereabouts of the three objects needed to kill Medusa (in other versions the whereabouts of Medusa) by ransoming their shared eye for the information. Hesiod says, “the Graiai, with fair faces and gray from birth, and these the gods who are immortal and men who walk on the earth call Graiai, the gray sisters, Pemphredo robed in beauty and Enyo robed in saffron.”
Clotho (/ˈkloʊθoʊ/, Greek Κλωθώ [klɔːtʰɔ̌ː] "spinner") spun the thread of life from her distaff onto her spindle. Her Roman equivalent was Nona ("the ninth"), who was originally a goddess called upon in the ninth month of pregnancy.
Lachesis (/ˈlækɪsɪs/, Greek Λάχεσις [lákʰesis] "allotter" or drawer of lots) measured the thread of life allotted to each person with her measuring rod. Her Roman equivalent was Decima ("the Tenth"). Normally seen clothed in white.
Atropos (/ˈætrəpɒs/, Greek Ἄτροπος [átropos] "inexorable" or "inevitable", literally "unturning", sometimes called Aisa) was the cutter of the thread of life. She chose the manner of each person's death; and when their time was come, she cut their life-thread with "her abhorred shears". Her Roman equivalent was Morta ("the dead one").
The Morrígan is often described as a trio of individuals, all sisters, called "the three Morrígna". Membership of the triad varies; sometimes it is given as Badb, Macha and Nemain. Mor may derive from an Indo-European root connoting terror, monstrousness cognate with the Old English maere (which survives in the modern English word "nightmare") and the Scandinavian mara and the Old East Slavic "mara" ("nightmare"); while rígan translates as "queen". This etymological sequence can be reconstructed in the Proto-Celtic language as *Moro-rīganī-s. Accordingly, Morrígan is often translated as "Phantom Queen". Her role was to not only be a symbol of imminent death, but to also influence the outcome of war. Most often, she did this by appearing as a crow flying overhead, and would either inspire fear or courage in the hearts of the warriors. In some cases, she is written to have appeared in visions to those who are destined to die in battle as washing their bloody armor. In this specific role, she is also given the role of foretelling imminent death with a particular emphasis on the individual. There are also a few rare accounts where she would join in the battle itself as a warrior and show her favoritism in a more direct manner.
The Norns are female beings who rule the destiny of gods and men in Norse Mythology. The Völuspá, Prophecy of the Völva (Seeress), is the first and best known poem of the Poetic Edda. It tells the story of the creation of the world and its coming end. Urðr (Wyrd), Verðandi and Skuld, the three most important of the Norns, come out from a hall standing at the Well of Urðr or Well of Fate. They draw water from the well and take sand that lies around it, which they pour over the Yggdrasill tree so that its branches will not rot. These three Norns are described as powerful maiden giantesses (Jotuns) whose arrival from Jötunheimr ended the golden age of the gods. Beside these three famous Norns, there are many others who appear at a person's birth in order to determine his or her future. In the pre-Christian Norse societies, Norns were thought to have visited newborn children. There were both malevolent and benevolent Norns: the former caused all the malevolent and tragic events in the world while the latter were kind and protective goddesses.
The Poetic Edda says about them (which I found interesting in this context):
"Of many births the Norns must be, Nor one in race they were; Some to gods, others to elves are kin, And Dvalin's daughters some."
The three wise women of Westeros do not appear to be sisters at all, but rather “of many births”, and one is literally a dwarf (Dvalin’s daughter).
I would contend that the following three wise old woman of Westeros can be loosely equated to the various aspects of the these mythological trinities:
“She was a very ugly old woman, Bran thought spitefully; shrunken and wrinkled, almost blind, too weak to climb stairs, with only a few wisps of white hair left to cover a mottled pink scalp. No one really knew how old she was, but his father said she'd been called Old Nan even when he was a boy. She was the oldest person in Winterfell for certain, maybe the oldest person in the Seven Kingdoms. Nan had come to the castle as a wet nurse for a Brandon Stark whose mother had died birthing him.”
-Game of Thrones, Bran IV
Pemphredo – alarm – she who guides the way – the well clad or robed in beauty
The Grey Ones are ancient, although they may have once been “fair cheeked” or beautiful. I suspect Old Nan was once a great beauty and also is the three eyed crow from Bran’s dreams who attempted to show Bran the way. Nan is toothless, like a bird, and her eye/hair color is never given, she has a ‘third eye’ in her needle (click click click and the three eyed raven spoke in a voice as sharp as swords, like a needle), she smells dragons when discussing the comet, and Bran gets no more “Princes” from her than he ever had.
Clotho – The Past – The Spinner – The Ninth - Nona
Old Nan is incredibly old, tells stories of the past, is always sowing (click click click), and originally came to Winterfell to care for a newborn Brandon Stark (the ninth is a reference to the nine months of maternity leading to childbirth).
Badb – Crow – prophesized the worlds end – “bean-sidhe” (a female spirit in Irish mythology who heralds the death of a family member, usually by wailing, shrieking, or keening.)
"I dreamed about the crow again last night. The one with three eyes. He flew into my bedchamber and told me to come with him, so I did. We went down to the crypts. Father was there, and we talked. He was sad."
– Game of Thrones, Bran VII
Obviously, this is all tied to my belief that Old Nan is the Three Eyed Crow, who is a messenger of death, and warns of the worlds end, “and now you know why you must live”.
Urdr – fate – Past – Urd’s well is the “well of fate”
"You be quiet, stupid," the girl said, tossing her own branch aside. "It's just water. Do you want Old Nan to hear and run tell Father?" She knelt and pulled her brother from the pool, but before she got him out again, the two of them were gone.
After that the glimpses came faster and faster, till Bran was feeling lost and dizzy. He saw no more of his father, nor the girl who looked like Arya, but a woman heavy with child emerged naked and dripping from the black pool, knelt before the tree, and begged the old gods for a son who would avenge her. Then there came a brown-haired girl slender as a spear who stood on the tips of her toes to kiss the lips of a young knight as tall as Hodor. A dark-eyed youth, pale and fierce, sliced three branches off the weirwood and shaped them into arrows. The tree itself was shrinking, growing smaller with each vision, whilst the lesser trees dwindled into saplings and vanished, only to be replaced by other trees that would dwindle and vanish in their turn. And now the lords Bran glimpsed were tall and hard, stern men in fur and chain mail. Some wore faces he remembered from the statues in the crypts, but they were gone before he could put a name to them.
-Dance with Dragons, Bran III
Nan is not only a fixture of Winterfell, with its heart tree above the still cold pool, but she is always telling stories of the past, and I would suggest she is even featured in a vision of the past through the tree of Winterfell including the pool.
Ghost of High Heart:
Beside the embers of their campfire, she saw Tom, Lem, and Greenbeard talking to a tiny little woman, a foot shorter than Arya and older than Old Nan, all stooped and wrinkled and leaning on a gnarled black cane. Her white hair was so long it came almost to the ground. When the wind gusted it blew about her head in a fine cloud. Her flesh was whiter, the color of milk, and it seemed to Arya that her eyes were red, though it was hard to tell from the bushes. "The old gods stir and will not let me sleep,"
"I dreamt a wolf howling in the rain, but no one heard his grief," the dwarf woman was saying. "I dreamt such a clangor I thought my head might burst, drums and horns and pipes and screams, but the saddest sound was the little bells. I dreamt of a maid at a feast with purple serpents in her hair, venom dripping from their fangs. And later I dreamt that maid again, slaying a savage giant in a castle built of snow." She turned her head sharply and smiled through the gloom, right at Arya. "You cannot hide from me, child. Come closer, now." – Storm of Swords, Arya VIII
Deino – Dread – the terrible
It should be noted that not only is the Ghost of High heart giving dread prophesies here, but a maid with serpents in her hair sounds a lot like a medusa, whom the grey ones pointed Perseus to in legend.
Lachesis – The present - The allotter – Measurer with her rod – Garbed in white - The Tenth – Decima
She has her gnarled black cane, and is pale as milk, which match with the measurer and garbed in white. Decima/Lachesis was in charge of determining the length of mortals’ lives, and along with Nona attended childbirths. The tragedy at Summerhall, to which the Ghost of High Heart refers when speaking to Arya, was the time and place of Rhaegar’s birth. She also predicted the promised prince would be of the line of Aerys and Rhaella.
Macha – sovereignty goddess - the land, fertility, kingship, war and horses – of the plain - "the mast of Macha"
High Heart itself is situated as the lone highpoint amidst a flat plain, giving clear line of sight all around. It was a sacred place to the Children of the Forest.
“The Mast of Macha” refers to the heads of men that have been slaughtered, stacked after a battle, and likely derives from a legend of a mother earth like goddess (Macha) who cared for men (a king) but was horribly mistreated (forced to race horses while pregnant despite pleading for reprieve) and so cursed men and became a war goddess. The masts, berries or nuts of the forest, which fed pigs (fruits of the land) being replaced with the heads of the slaughtered (fruits of battle).
High heart is also the location of a battle, and subsequent slaughter, then the chopping down of its 31 Weirwoods, resulting in a pile of corpses, or the mast of macha.
The great hill called High Heart was especially holy to the First Men, as it had been to the children of the forest before them. Crowned by a grove of giant weirwoods, ancient as any that had been seen in the Seven Kingdoms, High Heart was still the abode of the children and their greenseers. When the Andal king Erreg the Kinslayer surrounded the hill, the children emerged to defend it, calling down clouds of ravens and armies of wolves...or so the legend tells us. Yet neither tooth nor talon was a match for the steel axes of the Andals, who slaughtered the greenseers, the beasts, and the First Men alike, and raised beside the High Heart a hill of corpses half again as high...or so the singers would have us believe.
- The World of Ice and Fire, The Riverlands
Verdandi – happening/becoming – present
It should be noted that the Norns were of many births, one of which was a child of Dvalin (aka a dwarf!) just like the ghost of high heart.
Verdandi is commonly translated as from the root verda, “in the making”. The prophesies of the Ghost of High Heart are all about events which are in the making, as opposed to Nan’s stories of the past or Maggy’s foretelling deaths themselves.
Maggie the Frog:
The inside of the tent was full of smells. Cinnamon and nutmeg. Pepper, red and white and black. Almond milk and onions. Cloves and lemongrass and precious saffron, and stranger spices, rarer still. The only light came from an iron brazier shaped like a basilisk's head, a dim green light that made the walls of the tent look cold and dead and rotten. Had it been that way in life as well? Cersei could not seem to remember.
The sorceress was sleeping in the dream, as once she'd slept in life. Leave her be, the queen wanted to cry out. You little fools, never wake a sleeping sorceress. Without a tongue, she could only watch as the girl threw off her cloak, kicked the witch's bed, and said, "Wake up, we want our futures told." – A Feast for Crows, Cersei VIII
Enyo – horror – robed in saffron
The Westerlings always did have more honor than sense. Lady Sybell's grandfather was a trader in saffron and pepper, almost as lowborn as that smuggler Stannis keeps. And the grandmother was some woman he'd brought back from the east. A frightening old crone, supposed to be a priestess. Maegi, they called her. No one could pronounce her real name. Half of Lannisport used to go to her for cures and love potions and the like." He shrugged. "She's long dead, to be sure. And Jeyne seemed a sweet child, I'll grant you, though I only saw her once. But with such doubtful blood . . ." -Storm of Swords, Tyrion III
Not only does the tent of Maggy the Frog smell of saffron and spices, but her descendent goes on to found house Spicer. Her eyes are yellow as the eyes of death, and she instills horror in others.
Atropos – The Future – Inevitability – Cutter of threads - The Dead One – Morta
"Some are here who have no futures," Maggy muttered in her terrible deep voice. She pulled her robe about her shoulders and beckoned the girls closer. "Come, if you will not go. Fools. Come, yes. I must taste your blood."
Melara paled, but not Cersei. A lioness does not fear a frog, no matter how old and ugly she might be. She should have gone, she should have listened, she should have run away. Instead she took the dagger Maggy offered her, and ran the twisted iron blade across the ball of her thumb. Then she did Melara too.
- A Feast for Crows, Cersei VIII
In order to tell Cersei and the other girls how they will die, they must be cut and let her taste a drop of blood.
Morta is responsible for the pain and/or death that occur in a half-wake, half-sleep time frame, and we get this vision through Cersei half remembering and half dreaming.
Nemain – seize/take/deal out (possibly related to the Greek, “Nemesis”) - frenzied havoc of war - bean nighe or “washerwoman”, an omen of death.
In the grand Irish epic of the Tain Bo Cuailnge, Neman confounds armies, so that friendly bands fall in mutual slaughter.
Maggy causes/predicts that Cersei will kill her friend, pushing her down a well. And Maggy’s decedents cause the Red Wedding.
Maggy also presents Cersei with “the Valonquar”, her nemesis, who is destined to destroy her.
The old woman's eyes were yellow, and crusted all about with something vile. In Lannisport it was said that she had been young and beautiful when her husband had brought her back from the east with a load of spices, but age and evil had left their marks on her. She was short, squat, and warty, with pebbly greenish jowls. Her teeth were gone and her dugs hung down to her knees. You could smell sickness on her if you stood too close, and when she spoke her breath was strange and strong and foul.
- A Feast for Crows, Cersei VIII
Not only does she have no teeth, but some distinguishing characteristic of a bean nighe are being short and squat, small and green, and described as having unusually long breasts, or dugs. If caught they will reveal a man’s fate, or grant wishes... depending on the tale.
Skuld – debt – future – a Valkyrie
Skuld is the youngest of the Norns, as Maggy is the youngest of these three wise women of Westeros. She is both a Norn and a Valkyrie, not only “the one who cuts” or determines lives’ ends, but also marks significant changes, such as marriages and births… both of which are major parts of Maggy’s predictions to Cersei and company. Maggy’s decedents also bring about the Red Wedding, or a feast of the dead, which is what a Valkarie selected soldiers on the battlefield for, to feast in Odin’s Halls. Jeyne Westerling cared for Rob who was injured on the battlefield, before delivering him to the Red Wedding.