His eyes met Dany's and it seemed as if he saw her standing there beyond the door. 'There must be one more,' he said, though whether he was speaking to her or the woman in the bed she could not say. 'The dragon has three heads.' - Dany's Vision in the House of The Dying. A Clash of Kings, page 701.
The original novel, A Game of Thrones, came out in 1996. It was followed by A Clash of Kings in 1998 and A Storm of Swords in 2000. It would be another full decade before the series, under the name Game of Thrones, came to television.
In that time, fans of the books assisted by rapidly growing online communities came up with all sorts of theories as to how the end of the series would play out. When A Feast For Crows arrived in 2005, and provided few answers, these fan theories began to take on a fever pitch.
Some of these theories are now known far and wide, to show watchers and book fans alike. R+L=J (Rhaegar plus Lyanna equals Jon) was one of these theories. Another, "Azor Ahai aka The Prince That Was Promised is Jon Snow", looks like it may also be on the verge of being confirmed by the production this coming season.
Then there's "The Dragon Has Three Heads" theory. Taken from Dany's vision from The House of The Undying, there is a scene where Rhaegar turns and seemingly says directly to the sister he never knew: "The dragon had three heads." But what does that mean?
Well, Dany gave birth to three dragons right? That means we need three dragon riders, right? That means we need three Targaryens, right?
The first is obviously Dany, and her mount is Drogon. The second "seekrit!Targaryen" we have confirmed is Jon Snow, whose name might be Jaehaerys Targaryen. We have it confirmed he's going to meet Dany in Season 7. Can making himself a dragon friend be far behind?
So who is the third head?
The long-standing theory book readers have held, since the late '90s, is that Tyrion Lannister is our other "seekrit!Targaryen." The evidence comes from the book's description of the character when we first meet him.
He was a dwarf, half his brother's height, struggling to keep pace on stunted legs. His head was too large for his body, with a brutes squashed in face beneatha swollen shelf brow. One green eye and one black one peered out from under a lank fall of hair so blonde it seemed white. - A Game of Thrones, page 51
Who has blonde hair so pale it seems white? Targaryens. Who are described as having indigo eyes so dark they seem black? Targaryens.
Mix that with broad hints in conversations, and other things left half-said throughout the novels, that suggest Mad King Aerys had a thing for Tywin's wife Joanna Lannister, lady-in-waiting to Princess Rhaella in King's Landing.
In the novels, more than one person mentions how Joanna abruptly left court (with vague airs suggesting there had been some incident), only to turn out to be pregnant with Tyrion. Then she died birthing him. Add to that a detail from The World of Ice and Fire about Targaryen "monster babies,", which cause their mothers to die in childbirth, and you can see where all this is going.
Is Tyrion actually a Targaryen? The show didn't bother with the indigo eye, nor with the silver-white blonde hair. But that could be just as much due to Peter Dinklage's demands that he not look like your typical "fantasy dwarf" than anything else.
The visions in The House of The Undying that Dany saw on screen were also paired back, and the Rhaegar one cut. But keeping the visions simple was deliberate on the part of the production at the time. They didn't want to lock themselves into certain images too early or give away spoilers. (One of the visions, for instance, is the aftermath of the Red Wedding, which didn't happen until the next season.)
Tyrion does have an affinity for dragons. When meeting the ones in Dany's catacombs, he not only survived unchaining them but even almost seemed to make an emotional connection.
Could Tyrion be the third head? How many seekrit!Targs are there running around this joint? Will the real Targaryens please stand up?
Maybe we get another clue or two this season. Game of Thrones returns Sunday, July 16, at 9 p.m. ET, on HBO