Old Nan

Old Nan is a recurring character in the first season. She was played by Margaret John and debuts in "Lord Snow." Margaret John passed away on 2 February 2011, after the completion of filming for the first season. According to the writers the character passed away between the first and second season. Old Nan is an elderly servant at Winterfell, known for her storytelling.

Background
Old Nan is an elderly woman living in Winterfell. She is a retired servant of House Stark known for her tale-telling abilities. She has entertained the children of Eddard and Catelyn with stories throughout their childhoods. Her great grandson Hodor is a stable hand at the castle.

Season 1
After Catelyn Stark leaves for King's Landing, Old Nan sits by Bran Stark’s bedside to watch him. She suggests the story of Duncan the Tall and Bran replies that he hates her stories —he prefers the scary ones. She retorts that he is a "sweet summer child" who knows nothing about fear, and tells him that fear is for the winter and for the Long Night, a winter season thousand of years ago that lasted a generation, in which those who didn't freeze to death had to face the White Walkers, who ventured south for the first time and swept through Westeros. Theon Greyjoy interrupts another story and says that he would go mad if he was left alone with Old Nan.

Season 6
She is seen in the vision by Bran Stark, preventing Hodor, named Wyllis, to practice with young Benjen Stark, because Wyllis is a stableboy, and should not play with the nobles. Jon Snow and Sansa Stark later reminisce about the kidney pies Old Nan used to make for them as children.

Behind the scenes
Actress Margaret John, who played Old Nan, passed away only two months before Season 1 began to air, though all of her scenes had already been completed. The character does appear during the second book, however, in the TV series canon the showrunners decided to retire the character out of respect, so Old Nan is assumed to have quietly passed away between Season 1 and Season 2.

In the books
In A Song of Ice and Fire novels, Old Nan is the oldest person living at Winterfell. She came to Winterfell to act as wetnurse for a Brandon Stark, which one is unsure, only that his mother had died birthing him. This Brandon Stark is believed to be either the brother of Lord Rickard Stark or a brother of his father. She's retired but tells stories and legends to the Stark children. She lost two sons in Robert's Rebellion and her grandson during the Greyjoy Rebellion, while her daughters moved away and died. Her only surviving family is her great-grandson, the gentle, slow-witted Hodor.

In the books, it is Old Nan and not Osha who interprets the arrival of the Red Comet to mean the return of dragons.

"Nan" might be short for "Nymeria". When Arya Stark is on the run after escaping from King's Landing, one of the aliases she uses is "Nymeria", but she says to call her "Nan" for short.

Among the stories she used to tell the Stark boys are:
 * The last hero - who fought the White Walkers in the Long Night
 * The ice dragon
 * Harrenhal and Harren the Black
 * The Night's King
 * Symeon Star-Eyes
 * How the Children of the Forest taught the First Men to send messages by raven
 * The Rat Cook
 * The Mad Axe
 * The Thing That Came In The Night

Following the Sack of Winterfell, Old Nan is brought to the Dreadfort. Her fate is unknown.

The Season 6 episode "Home" showed a flashback to Eddard Stark as a young boy at Winterfell, along with a younger Nan and Hodor - with Hodor around the same age or slightly younger than Eddard. In the novels, it is heavily implied but not outright stated that Hodor is in his late teens or early twenties during the main narrative, and that his father was Old Nan's grandson who died in the Greyjoy Rebellion. In this case, Hodor obviously couldn't have been a child at roughly the same time as Eddard Stark and his siblings. However, in the TV version, Hodor is played by actor Kristian Nairn, who was 38 years old when Season 6 was filmed: there probably weren't many seven feet tall teenaged actors to pick from at the audition, so the TV series cast Nairn. This being the case, TV-Hodor simply happens to be twice as old as book-Hodor - and therefore, unlike his book counterpart, TV-Hodor actually is roughly in the same age group as Eddard Stark (Nairn is actually 15 years younger than Sean Bean, but even so, due to his unusually large size it is unclear exactly how old young Hodor is supposed to be in the flashback scenes).

This being the case, it is unclear if Old Nan is necessarily still Hodor's great-grandmother in the TV continuity, or just his grandmother. Assuming a generation gap of roughly 20 years, if Old Nan gave birth to Hodor's grandparent when she was 20, Hodor's parent would have been born when she was 40, and Hodor would have been born when Old Nan was around 60 - meaning old Nan would have to be in her mid-90's in the TV version. This is not necessarily implausible, given that Old Nan is supposed to be very old within the narrative: people in their medieval society tend to have children at young ages or in their late teens, so a man in his mid-30's with a living great-grandmother certainly isn't impossible. Given that no official retcon was ever stated, it is assumed that Old Nan is Hodor's great-grandmother, and her family just had children at relatively young ages.