A popular fan theory argues that Tyrion might be a Targaryen, perhaps even Mad King Aerys' son. The evidence was fairly weak until GRR Martin wrote The World of Ice and Fire, a history of Westeros. Here's the evidence in the order I feel is strongest to weakest: UPDATE #2: Added evidence found in The World of Ice and Fire. UPDATE: After watching the Season 3 finale, I am firmly convinced that Tyrion is not Tywin's son. Why? Tywin's closing comments "I will raise you as my son. Because you are a Lannister." You don't say these things to someone who is your son. 1. Tyrion's eye and hair color doesn't match his father or siblings. This is not apparent in the TV Show, but in the books it's very pronounced. Jaime and Cersi have the "typical" Lannister look, golden blonde hair and bright green eyes. Tywin also has these traits. However, (in the books) Tyrion has pale blonde hair, possibly a mix between Lannister golden blonde and Targaryen silver grey. Tyrion's eyes are mismatched - one is green, and the other is black, which is a common sign of cross-breeding. Also consider Tyrion's dwarfism, which seems to mirror another Targaryen trait - many Targaryen mothers gave birth to monstrosities similiar to the stillborn child Daenerys had at the end of the first book, scaly half-man-half-dragon creatures. Some even possessed wings. Tyrion is not nearly this ugly but could be a step in that direction considering the Lannisters are normally so beautiful. 2. Aerys Targaryen was infatuated with Joanna Lannister, Tywin's wife, and is rumored to have slept with her. This was common knowledge, as was Aerys' distaste for Tywin. From Barristan Selmy: Prince Aerys . . . as a youth, he was taken with a certain lady of Casterly Rock, a cousin of Tywin Lannister. When she and Tywin wed, your father drank too much wine at the wedding feast and was heard to say that it was a great pity that the lord’s right to the first night had been abolished. From the World of Ice and Fire (written by GRR Martin): It has been reliably reported that King Aerys took unwonted liberties with Lady Joanna's person during her bedding ceremony, to Tywin's displeasure. Not long thereafter, Queen Rhaella dismissed Joanna Lannister from her service. No reason for this was ever given, but Lady Joanna departed at once from Casterly Rock and seldom visited King's Landing. Joanna Lannister did make a raw appearance at King's Landing for the Anniversary Tournament in 272AC, when King Aerys embarrassed Joanna and Tywin in front of the full King's court. Less than 1 year later... Tyrion was born. If this theory is true, then we can easily understand why Tywin hates Tyrion - Tywin's wife died giving birth to another man's son, which Tywin must raise or risk public humiliation. 3. Tyrion was obsessed with dragons as a child, even dreaming about them. This was common among Targaryens. Still a weak bit of evidence. 4. Tywin says Tyrion isn't his son, multiple times. Of course, Tywin could be lying to wound Tyrion. However, this comment from Tywin is suspect: You are an ill-made, spiteful little creature, full of envy, lust and low cunning. Men's laws give you the right to bear my name and display my colors, since I cannot prove that you are not mine. 5. Tyrion survives contact with greyscale, and Targaryens may be immune to the disease. In A Dance With Dragons, Tyrion survives a nasty greyscale exposure untouched and yet Jon Connington, who rescues Tyrion, succumbs to the disease. Tyrion also survives exposure to the bloody flux. Daenerys Targaryen believed her family was immune: “Have you ever seen a dragon with the flux?” Viserys had oft claimed that Targaryens were untroubled by the pestilences that afflicted common men, and so far as she could tell, it was true. She could remember being cold and hungry and afraid, but never sick. However, Maegelle Targaryen died of greyscale 200 years before the events in the books. Targaryens still may be immune, though. There is evidence that Targaryens have different levels of dragon blood within them. There have been many Targaryen babies born as stillborn monsters with scales and tails. Some Targaryens seem to have stronger blood then others. ---- To make things more confusing, there are rumors that Jamie and Cersi are Targaryen, while Tyrion is the only real Lannister. Tywin would look a fool if this is discovered, and thus he denies any relation to Tyrion so strongly that perhaps Tywin believes his own lies. Or so the theory goes. Tywin's sister Genna believes the twins are not Tywin's children: Jaime, sweetling, I have known you since you were a babe at Joanna's breast. You smile like Gerion and fight like Tyg and there's some of Kevan in you, else you would not wear that cloak...but Tyrion is Tywin's son, not you. I said so once to your father's face, and he would not speak to me for half a year. Of course, who knows if Genna was speaking of a truth she discovered or exercising an opinionated strong will, which she was known to have in plenty. The characters in Westeros all seem to possess half-truths, such that their insights reflect their personalities and weaknesses. In the end, there is a giant question mark about the Lannisters, without any real answers. 146.5k Views · View Upvotes Related QuestionsMore Answers Below Is it biologically possible for Tyrion Lannister to be both a Targaryen and a Lannister? What if Tyrion Lannister is not the nice guy we think he is? How would Ned Stark have raised Tyrion Lannister if he were his son? If Tyrion Lannister is a Targeryen, who can prove or give evidence about it in ASOIAF? Is Shae, Tyrion's friend, really a Targaryen? Kelsey L. Hayes Kelsey L. Hayes, I'm only here for the food symbolism. Written 14 Jul 2015 I think Jon is a Targaryen (Rhaegar's son with Lyanna) and that Tyrion is not. Green eyes are not a Targaryen feature; they're actually a Lannister feature. As is having yellow hair. There's nothing about Tyrion physically that would make anyone think he was a Targaryen (although the same is true with Jon). And while Aerys supposedly had a thing for Joanna Lannister, the vast amount of his proximity to her occurred years before Tyrion was even born. In terms of the timeline making sense, if any of Tywin's children are Aerys', it would be the twins, not Tyrion. 7.4k Views · View Upvotes · Answer requested by Abhay Gupta André Cesarino André Cesarino, enjoyed the books Updated 9 Sep 2015 Honestly, I find it very unlikely. Why? First, the "signs" some people point to: Aerys' lust for Tywin's wife, Joanna; Tywin constantly rejecting Tyrion; immunity to greyscale; Tyrion's attraction for dragons and Valyrian lore. OK, the first one, Aerys' lust for Joanna: Yes, it makes sense, but there is a great distance between lusting after a married woman and having sex with her often enough for a likely pregnancy. Besides, the timeline doesn't make much sense, let's see in the Asoiaf Wiki: Joanna married her first cousin, Tywin, in 263 AC in a lavish ceremony in the Great Sept of Baelor.[7] On their wedding day, Tywin smiled, a very rare occurrence.[8] However at the wedding feast, Aerys drunkenly japed about how it was a pity the first night tradition was banned, and he took certain "unwonted liberties" with Joanna in the bedding ritual when the men at the feast had to disrobe the bride.[9][6] Not long thereafter, Joanna was dismissed by Queen Rhaella from her service in King's Landing. While Queen Rhaella turned a blind eye towards most of her husband's infidelities, she did not approve when it concerned one of her own "ladies." (Joanna was one of many ladies to be sent away from court.) She departed for Casterly Rock at once, and seldom visited King's Landing afterwards. If Joanna was dismissed from court by Queen Rhaella before Joanna had any children, and Joanna returned to Casterly Rock, seldom visiting King's Landing, how would Joanna and Aerys even meet, in the first place? Besides, Joanna's marriage was a very happy one, according to many witnesses, so the only way I could see Aerys having sex with Joanna after her return to Casterly Rock is through rape, which makes it even likelier to be noticed. My opinion? Aerys lusted after Joanna, yes, but Queen Rhaella quickly noticed that and sent Joanna away, which happened years before Joanna had children. If Aerys had sex with Joanna when she was at court, it ensued no children and had no bearing in story. Second tip: Tywin constantly rejecting Tyrion. Tywin rejects Tyrion because Tyrion doesn't have what Tywin would call "Lannister pride", because Tyrion is a dwarf who seeks whores (his father Tytos had the same weakness), and, in his opinion, is unsuited to rule Casterly Rock. Tywin never had any plausible reason to deny Tyrion as his son, that's why he keeps him alive. Third tip: Immunity to greyscale Sorry, Targaryens do get sick, contrary to what Dany says to herself. Dany herself gets diarrhea from eating poisonous berries. An older example would be Daeron the Good, who died in the Great Spring Sickness. Besides, Tyrion only had a one-time only contact with greyscale, it doesn't mean he is immune to it. Fourth tip: Dragons and Valyrian lore Tyrion was born a dwarf, he quickly realizes he won't be a knight like his brother Jaime. So, what to do? Make up for his physical deficiencies with knowledge. And, if he had a dragon and could fly sky high, why would being a dwarf matter? Tyrion's dreams about dragons were childish imagination, but his thirst for knowledge remained. "That's why I read so much, Jon Snow." From a storytelling perspective: Tyrion is a survivor in the story, and after fleeing from Westeros, he has only his wits. In fact, he is the embodiment of the Lannister characteristics (cleverness, creativity, quick thinking, diplomacy). Giving him a secret Targaryen lineage would sort of undermine his character and, in my opinion, doesn't fit very well in the story. In fact, if I were to bet on secret Targaryen bastards, I would bet a lot more on Cersei + Jaime. The timeline doesn't work well, but at least it would explain why they couldn't stop humping each other through most of their lives.