One of the most valuable lessons ofGame of Thronesis that the people in charge of the world might not be on top for a reason. Many are born into power without anyone considering how cruel or incompetent they’ll be at wielding it. House Targaryen is the former royal house of the Seven Kingdoms, but the genetic line that confers the throne also hands down the dreaded Targaryen Madness.

Do mostGame of Thronesfans have a favorite noble family? They certainly have favorite characters, but is there a house they’d like to see take the Iron Throne? If one were to poll every fan, House Stark, House Lannister,or House Martell wouldlikely take the gold medal. It’s hard to imagine anyone picking House Targaryen.

Game of Thrones Viserys Targaryen

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What causes Targaryen Madness?

Around half of House Targaryen is born with severe mental illness that reveals itself in later life. Medically speaking, conditions including schizophrenia and bipolar disorder have a genetic component. Targaryen Madness isn’t a specific illness. It began hundreds of generations before Aegon the Conquerer tookover most of Westeros. Targaryen Madness is a natural result of constant incest throughout the family tree. The Targaryens are the last of the 40 original dragonlord families from Valyria. They hailed from a culture that regularly married brothers and sisters to maintain a “pure” bloodline. This process resulted in regular genetic defects. This concept mirrors historical royal dynasties like the Habsburgs, who routinely used incest to keep power within their family.

House Targaryen’s propensity for incestwas well-known throughout the Seven Kingdoms. It was said that every time a Targaryen was born, the gods flipped a coin. The phrase had two meanings. It implied that roughly fifty percent of the Targaryen bloodline would suffer their genetic madness. The Faith of the Seven, themost popular religion in Westeros, forbade incest. Many believed the mental instability was a curse from the deities angered by their unacceptable actions. King George III of England famously suffered from fits of madness. Modern explanations include porphyria and bipolar disorder, but George was almost certainly a product of incest. This aspect of the story reflects the grim truth of royal bloodlines.

Old King Jaehaerys I Targaryen at the Great Council of 101 AC in House of the Dragon.

Which Targaryens are mad?

The most famous example of Targaryen madness is Aerys II. The Mad King was the 16th Targaryen to sit on the Iron Throne. His early reign was peaceful and uneventful. Aerys developed something akin to paranoid schizophrenia. He heard voices, made wild accusations, and suspected everyone he saw of plotting against him. During a revolt over taxes, Aerys was kidnaped and tortured for six months. Ser Barristan Selmy rescued Aerys, who likely would have died when his Hand, Tywin Lannister, sacked the town. Ser Barristan would spend his remaining 26 years of life regretting his success.

When Aerys returned to the throne, his reigndescended into blood and fire. He despised Tywin and the rest of his small council. When Aerys’s oldest son kidnaped Lyanna Stark, the noble houses started to rebel. Brandon Stark rode to King’s Landing to save his sister, so Aerys had him arrested for treason. When Brandon’s dad, Rickard, arrived to pay his son’s ransom, Aerys executed both. This was the start of Robert’s Rebellion, in which the forces of the realm worked together to depose the Mad King. Jon Arryn, Eddard Stark, Robert Baratheon, and even Tywin Lannister called their banners and marched on King’s Landing. Their overwhelming might triggered the Mad King’s trap card. He had secretly employed the Alchemist’s Guild to hide stashes of explosive wildfire all over the city. Half a million lives would’ve ended in a flash, but a hero laid down his honor to save them. Jamie Lannister, Lord Commander of the Kingsguard, killed King Aerys II Targaryen, allowing Robert Baratheon to take the Iron Throne.

Daenerys and Jorah Mormont in the Battle of Winterfell in Game of Thrones.

Aerys IIwas the most iconicMad King, but he wasn’t the first. Baelor the Blessed, the ninth Targaryen king, became a self-destructive religious zealot. He ordered the construction of the Great Sept, the center of worship in King’s Landing. He built the Maidenvault to lock away his sisters. Not because he was against incest but because he was against sex. He eventually starved to death after deciding that food was of this world and, therefore, sinful. Four generations later, Prince Rhaegel became known for dancing naked through the halls of the Red Keep. Perhaps most tragically, Prince Aerion Brightflame succumbed to the madness and drank wildfire. He believed he’d be reborn as a dragon. Instead, he died an agonizing death. Many other Targaryens exhibited sociopathy or abnormal cruelty, but the maddest examples stand out.

Does every Targaryen go mad?

The unseen hand of Targaryen madness is cruel and random. Not every family member succumbs to its influence, but there’s no way of knowing who will and won’t fall prey. Some viewers of the showhave argued that Daenerysgave into Targaryen madness around season eight. It’s a better explanation for her actions than any offered by the series.Jon Snow, the lastliving son of Rhaegar Targaryen, seems well within his right mind, but he’s still a young man. The books have demonstrated Targaryen madness in children who weren’t the direct product of incest. The bloodline is tainted from generations of awful decisions. Some will be free from the genetic curse, but it can sneak up at any moment.

Targaryen madness is a revolting but historically accurateaspect ofGame of Thrones' depiction of royalty. The Mad King should be blamed for his actions, but he carries the mental scars of hundreds of sisters and brothers before him. The downfall of House Targaryen had to come eventually, whether by the sword or by the slow death of congenital disorders.