- "Unlike some other houses, my ancestors earned the Bolton words: "Our Blades Are Sharp". They passed down not a Valyrian greatsword but a knife, honed and thin enough to fit between the topmost layer of skin and the tissue below... and peel... For as we all learned as children: A naked man has few secrets... a flayed man, none."
- ―Roose Bolton
Flaying, otherwise known as skinning, is an ancient, and particularly frowned upon method of torture and execution, which involves the use of a blade to remove several layers of the victim's skin, exposing nerve and muscle tissue, and leaving them in perpetual agony, assuming they survive the ordeal at all.
- "In those dark days they said some of my more... willful forebearers would even wear their enemies' skins as cloaks. But no such tokens remain, if they ever existed... certainly not hanging in some secret room in the Dreadfort as old wives and fools insist."
- ―Roose Bolton.
The practice of flaying is commonly and notoriously associated with House Bolton, an ancient northern house with blood of the First Men dating back to the Age of Heroes, to the point that they took a flayed man as their sigil. Members of the family and their household are fond of saying "A naked man has few secrets; a flayed man, none".
Boltons were rumored to go as far as wear the skins of their executed enemies as cloaks and display them on a chamber within their family seat, the Dreadfort. They supposedly gave up these practices when they bent the knee to House Stark and agreed to become their vassals. Nevertheless, the practice was still rumored to continue in secret, while their age-old saying was still taught to the children of the family.
Following the Battle of Oxcross, Roose Bolton attempts, unsuccessfully, to persuade King Robb Stark to torture officers captured in battle, citing his family saying of flayed men keeping no secrets. King Robb reminds Lord Bolton that his father outlawed flaying in the North, and that he does not want to give the Lannisters a reason to abuse his sisters in King's Landing (although Joffrey has Meryn Trant beat Sansa in public anyway). Roose cites Robb's rejection of this advice, among others, as one of his reasons for his betrayal and murder of Robb at the Red Wedding.
After Theon Greyjoy is betrayed by his own crew and delivered to Ramsay Snow in exchange for free passage from Winterfell to the Iron Islands, the bastard son of Roose Bolton turns on the ironborn, captures them and flays them alive. Theon himself is partially flayed by Ramsay in captivity. Months later, in a letter sent to Balon Greyjoy, Ramsay promises to hunt down and flay alive all ironborn that have invaded the North.
- "It's fallen out of fashion... flaying. Sad, but true. Traditions are important! Where are we without our history? Eh?"
- ―Ramsay Bolton defends the practice of flaying.
To ensure the surrender of Moat Cailin, Ramsay Snow promises the besieged ironborn garrison that if they leave, he will grant them safe passage back to the Iron Islands. This is the same promise he made to the ironborn who took Winterfell, and just as before, as soon as the ironborn surrender Ramsay immediately breaks his promise and has all of the ironborn flayed alive and their mutilated corpses put on display. Though obviously disappointed with Ramsay's conduct, Roose is impressed that Ramsay succeeded in taking the castle, and so he rewards him by finally showing him the royal decree of legitimization which he obtained from the Lannisters, acknowledging Ramsay as his son and rightful heir, and renaming him "Ramsay Bolton".
When Lord Medger Cerwyn refuses to pay his taxes to the new Wardens of the North, Ramsay flays him, his wife, and his brother alive in front of his son Cley. Cley pays his taxes and the flayed bodies are hung from Winterfell's walls. Roose scolds his son, saying that the other lords will not indefinitely tolerate open intimidation. Ramsay later flays an old maid living for attempting to help Sansa escape from Winterfell, but begrudgingly admits that she refused to talk and only died because her heart gave up from the stress before he could flay her face.
After Sansa escapes from Winterfell to seek refuge with Jon Snow at Castle Black, Ramsay sends Jon a letter in which he he threatens to have the wildlings Jon saved from Hardhome flayed alive if Sansa is not returned to him.
Prior to the Battle of the Bastards, Ramsay places six flayed corpses, among them possibly the bodies of Roose Bolton, Walda Bolton and Osha, on fire across Winterfell's lands to intimidate Jon Snow and his followers. Following the battle and House Stark retaking Winterfell and the North, since flaying was previously outlawed by Eddard Stark, Ramsay is executed by being devoured by his own hounds; thus while he is not flayed, his skin is torn from his body in order to draw his agony out.
During a meeting between numerous Northern lords, Lyanna Mormont chides Cley Cerwyn for not having helped Jon, reminding him that Ramsay previously flayed his father, mother and uncle alive. With Jon's ascension to King in the North and House Bolton's extinction, it is likely he will follow in Eddard's footsteps and outlaw flaying once again, this time for good.
In the aftermath of the Sack of Highgarden, Jaime Lannister revealed to Olenna Tyrell that flaying was among Cersei Lannister's plans to painfully execute her, but he talked her out of it and gave Olenna a merciful death by poison.
In the books
In the A Song of Ice and Fire novels, the practice of flaying is synonymous with House Bolton, to the point where a bloody, skinless man became their sigil. Their house words: "Our Blades Are Sharp", also reflects House Bolton's penchant of torture.
A thousand years prior to the War of the Five Kings, the Boltons bent the knee to the Kings in the North and were forced to abandon their tactic of flaying their captives. However, three hundred years later the Boltons rose in rebellion against the Starks of Winterfell. The Stark armies besieged the Dreadfort for two years before the Boltons finally yielded. For many centuries the Boltons remained grudgingly subservient to the Starks, although rumors persisted that they continued to flay their prisoners in secret, and maintain a hidden chamber in the Dreadfort to display the skins of their enemies. Rumor has it that the skins of several Starks are among the most prized in the collection.
There is no mention of Ned Stark ever outlawing the practice of flaying in the North.
In real life Medieval Europe, flaying a person alive was rare but not unknown. Perhaps the most infamous example was when King Richard I of England died. While besieging a castle in southern France, Richard was hit by a crossbow bolt in the shoulder, but the wound soon became gangrenous, and he died about two weeks later from the infection. As he lay bedridden with fever, his forces took the castle, and brought to him the person who shot the crossbow bolt - a young boy named Pierre. Expecting to be executed for causing Richard's death, Pierre defiantly explained to him that Richard's army had killed his father and two older brothers in prior battles, and thus killing Richard was his just revenge. Ever the model of chivalrous behavior, Richard was so impressed with the boy's bravery and explanation that he ordered him to be set free and returned to enemy lines. The mercenaries under Richard's command did not honor his last request, however: as soon as Richard died, they not only executed young Pierre, but had him flayed alive.
During the Dark Ages in England, flaying was also a punishment meted out to Viking invaders in the Saxon Kingdom of Essex. Whose remains were nailed to church doors in the county as a warning to others.