Aemon

Maester Aemon is a recurring character in the first and third seasons. He is played by guest star Peter Vaughan and debuts in "Lord Snow."

Aemon is the maester at Castle Black and is one of Lord Commander Jeor Mormont's closest advisers in the Night's Watch.

He was born Aemon Targaryen and is the last Targaryen in Westeros. He is the great-uncle of Daenerys Targaryen, currently in exile in Essos and unaware of his existence. Aemon's origins have long been forgotten by most, as he has remained dedicated to his vows as a Maester and a brother of the Night's Watch for decades uncounted.

Background
Aemon was born into House Targaryen. He dropped his House name when he joined the order of Maesters. Around one hundred years old, Aemon is thought to be one of the oldest living men in Westeros, though he has retained all of his wits and his mind is still very sharp. He has served as the Maester at Castle Black for many decades.

Aemon has long since gone blind due to old age. It is not clear when he went blind (he was not born blind), though he has stated that he was already old and blind during Robert's Rebellion.

Season 1
After Tyrion Lannister has arrived at Castle Black, Maester Aemon asks him to urge the Queen to send more men to the Night's Watch: there is a severe lack of men to defend the Wall. They discuss the coming winter, and Aemon assures Tyrion that the next winter will be long and terrible. Lord Commander Mormont is worried about rumors of White Walkers abroad north of the Wall. He sends Benjen Stark ranging to investigate.

When Jon Snow and the other new recruits are done with their first training, Maester Aemon gives the new stewards their assignments. Jon is to become Jeor Mormont's steward, which is a great disappointment to Jon: he had hoped to become a ranger. Samwell Tarly is assigned as Aemon's steward. Sam reminds Jon that being a steward for the Lord Commander might mean that Jon is being groomed for a high position amongst the Night's Watch. The bodies of two of the rangers who accompanied Benjen are found near the Godswood. The Lord Commander plans to have Aemon examine them but they return as wights and have to be burned before he does so.

When Jon hears about Eddard Stark's imprisonment, he is torn between his loyalty to the Night's Watch and his love for his family. Maester Aemon intercepts Jon as he is preparing to desert the Watch. Aemon says he is aware of Jon's struggle and reveals to him that his real name is Aemon Targaryen, and that he is a long forgotten uncle of the Mad King. He sat and waited on the Wall whilst he heard about his family being butchered during Robert's Rebellion and the few survivors fleeing into exile, and did nothing: after having joined the Watch, his duty was with his brothers there and no longer with his House. Aemon explains that this was a difficult decision; yet he had to make it and that one must live with the consequences of one's choices for the rest of one's life. Maester Aemon remains at Castle Black during the Lord Commander's great ranging.

Season 3
Maester Aemon is still at Castle Black when Samwell Tarly returns with Gilly after escaping from Craster's Keep. Aemon at first advises Sam that he swore an oath when joining the Night's Watch, believing that Sam fathered Gilly's son. Samwell corrects him that he is not the father, but that the girl is one of Craster's daughter-wives, which engenders sympathy in Aemon. Because it is too dangerous beyond the Wall, Aemon relents and offers shelter to Gilly in Castle Black for the time being. Gilly thanks him and calls him "my lord", but Aemon insists that he gave up being a lord many years ago (when he joined the Order of Maesters and left House Targaryen). With the matter settled, Aemon commands Samwell to make sure all of the messenger-ravens are well-fed, and tells him to take a quill and parchment: he dictates to Samwell a request for help which will be sent to all the major lords throughout the Seven Kingdoms, imploring them for aid against the threat of the White Walkers.

Quotes
"The Night's Watch is the only thing standing between the realm and what lies beyond and it has become an army of undisciplined boys and tired old men. There are less than a thousand of us now. We can't man the other castles on the Wall. We can't properly patrol the wilderness. We have barely enough resources to keep our lads armed and fed."

- Maester Aemon to Tyrion Lannister

In the books
In the A Song of Ice and Fire novels, Maester Aemon is widely believed to be one of the oldest living men in all of Westeros. He is nearly a hundred years old in the first novel, and advances into his 102nd year by the third novel (corresponding to his appearance in Season 3). He has been on the Wall for almost seventy years and is known for his great wisdom, wise counsel and trusted judgement. He is the third son of King Maekar I Targaryen, and the older brother of King Aegon V Targaryen ("Egg" from the Dunk and Egg short stories by George R.R. Martin), the uncle of King Jaehaerys II Targaryen and thus the great-uncle of the Mad King and the great-grand-uncle of Daenerys Targaryen. Aemon was actually offered the throne, being Maekar's eldest surviving son, but declined on account of his vows, thus allowing Aegon V "the Unlikely" to assume the throne. Aemon then joined the Night's Watch in the hope that having taken oaths as both a member of the maesters and then the Night's Watch to forsake any claim to inheritance, no one would think of him as a legitimate heir to be used as political pawn against his younger brother. Despite being isolated at the Wall for many decades and unable to travel due to his increasing age, Aemon knew Prince Rhaegar Targaryen well because they regularly corresponded via raven, making Aemon's decision not to leave the Wall all the more painful.

For the TV series, Jaehaerys II has been removed, with Aerys II being the son of Aegon V, thus the televised Aemon more closely related to Daenerys and Viserys, being their great-uncle instead of their great-great uncle.

In the books, Lord Commander Jeor Mormont makes it clear to Jon Snow that he is fully aware that Aemon is actually a Targaryen. However, he saw no reason to tell Robert Baratheon, as the rules of the Night's Watch are that any member sheds all previous family ties, and the Night's Watch are their family now. Further, Aemon was already a blind old man, and a respected member of the Night's Watch for decades. Aemon took no particular action in support of House Targaryen when it was overthrown by Robert, so Mormont was confident that Aemon held true to his vows and no longer considered himself a Targaryen.

Other characters later point out that it is somewhat unusual that Aemon, a respected member of the Order of Maesters for decades, was never promoted to the rank of Archmaester, to become part of the ruling Conclave in Oldtown. It is speculated that the Conclave was wary about making a member of the royal family an Archmaester, given the entanglements this might create with the Targaryens. Whatever the case, the entire reason that Aemon joined the Night's Watch was to move as far away from the centers of power as possible, so it is probable that even if he were asked he would have declined a promotion to Archmaester at the Citadel.

Aemon is 99 years old in the first novel. Actor Peter Vaughan was 88 years old during Season 1. While portraying the blind Aemon, Vaughan is himself partially blind.