Who Is Tyrion's Mother On 'Game Of Thrones'? Joanna Lannister's Backstory Could Hold A Vital Secret

If there's one thing that the Starks and Lannisters have in common, it's that they know a great deal about loss. Admittedly, given the rapid rate of character deaths on this show, the same could be said about pretty much everyone, however, the Starks and Lannisters in particular have seemed to face more than their fair share. And while we've seen many of these tragedies take place firsthand, there's one character that's been repeatedly mentioned, but always remained a bit of a mystery. I'm referring to Jaime, Cersei, and Tyrion's mom, Joanna Lannister, who's Game of Thrones background has never fully been explored. So who is Joanna Lannister and why could she potentially be so important, even in death? Like so many other characters on this show, she may have a game-changing skeleton in her proverbial closet.

As I'm sure most of you know already, there is a theory currently circulating right now about Tyrion's lineage, suggesting that he is actually a Targaryen. There has been a lot of evidence stacked up to support this claim, most recently due to Tyrion's successful attempt at taming Dany's dragons. (Does this also make him the Breaker of (Dragon) Chains now?) But a big chunk of this theory can be traced back to what readers learned about her in George R.R. Martin's novel. You see, Joanna was rumored to have had romantic ties to King Aerys (aka the Mad King) during her early years at court as a lady-in-waiting — an affair which may have continued long after she married Tywin Lannister.

Of course, that hardly qualifies as concrete evidence as to whether or not anything was really going on between them. However, I think it's safe to assume that King Aerys had very strong feelings for Joanna and made no secret about it, even though Tywin was the Hand of the King during his rule. In A Dance with Dragons , Ser Barristan said as much to Dany, though he made sure to choose his words very carefully:

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. A drunken jape, no more, but Tywin Lannister was not a man to forget such words, or the … the liberties your father took during the bedding.

And while Barristan doesn't elaborate on what these "liberties" might've been, it's relatively easy to connect the dots. Clearly, Aerys had no qualms with taking what he wanted, so who's to say it stopped there on her wedding night? There's no doubt the similarities that are shared between Cersei and Jaime in both demeanor and physical appearance. But can the same be said for Tyrion? He doesn't seem to prominently resemble his siblings in such an obvious way, which could indicate that he has a different father.

It's also important to note that Joanna is also the main cause for Tywin's continued hatred of Tyrion throughout the series. This has been primarily been explained due to the fact that Joanna died giving birth to Tyrion. (Cersei has openly admitted that she blames her brother for her mother's death.) So the tension between Tywin and Tyrion has always been chocked up to resentment over her death. But what if it's more than that?

Right before Tyrion killed Tywin (on his own personal throne), Tywin made the comment "You are no son of mine." Sure, it could be interpreted as one last insult simply meant to harm Tyrion and make him feel even more unloved. But perhaps it was actually Tywin finally admitting that Tyrion is the product of another man — a Targaryen to be more specific.

But regardless of whether or not this theory turns out to be true, for someone who has never set foot on screen, I think we can all agree that Joanna has played a vital part in the overall storyline and proves that the off-screen characters can be just as intriguing (if not more so) than their on-screen counterparts.

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