House Of The Dragon: The Real Reason The Targaryens Married Each Other

There are a few truths universally acknowledged in the "Game of Thrones" franchise. First off, don't get too attached to any characters, since they'll probably die. Blood and clothes will both be shed (usually not at once, but it's been known to happen). Also, there will be incest.

First "normalized" in the original "Game of Thrones" series — more on that in a bit — relations between family members has hit somewhat of a nadir, so to speak, in the first major spin-off and prequel "House of the Dragon." Within the first season, audiences watched as Princess Rhaenyra Targaryen, played in her teenage years by Milly Alcock and as an adult by Emma D'Arcy, started developing strange feelings for her uncle, Prince Daemon Targaryen (Matt Smith); the two ultimately marry in the seventh episode, "Driftmark." 

Rhaenyra's two eldest sons Jacaerys and Lucerys (Harry Collett and Elliott Grihault) are betrothed from a young age to Baela and Rhaena (Bethany Antonia and Phoebe Campbell), and if Jacaerys and Lucerys were the legitimate sons of Rhaenyra's first husband Laenor Velaryon (John MacMillan), they'd be engaged to their own cousins. (Luckily for that one aspect of their lives, Jacaerys and Lucerys were fathered by Ryan Corr's Ser Harwin Strong; Lucerys also dies before he can marry a girl he thinks is related to him). The children of Alicent Hightower (a young Emily Carey and an older Olivia Cooke) and King Viserys I Targaryen (Paddy Considine) end up marrying each other, in the case of Alicent's eldest son Aegon II Targaryen (Tom Glynn-Carney) and his sister-wife Queen Helaena (Phia Saban).

Okay, so — that's a lot of incest. But why is there so much incest on both "Game of Thrones" and "House of the Dragon," particularly amongst House Targaryen?

When it comes to the Targaryens, there was a "rationale" for keeping it in the family, for lack of a better term ... though what it led to certainly wasn't the intended outcome. During the time of "House of the Dragon," Targaryens, who were descended from Valyrians when you go even further back in the timeline of "A Song of Ice and Fire," encouraged inbreeding to keep bloodlines "pure" and ensure that they would not only still possess royal blood, but be able to form better bonds with their dragons. (It's said that only those of Targaryen descent can bond with dragons.) While not every Targaryen engaged in incest, it was a pretty common practice — which, unfortunately, bears similarities to some real incestuous royals throughout history — and what this led to was genetic "madness," to the point where it became common to say that whenever a Targaryen is born, "the Gods flip a coin" regarding their sanity.

The most egregious example of this, though we've never seen him depicted on-screen, is King Aerys II Targaryen, who marries his sister Rhaella and spawns three children: Rhaegar, Viserys (Harry Collett), and Daenerys Targaryen (Emilia Clarke). Unfortunately for Daenerys, it certainly seems like her father's genetic penchant for insanity gets her in the end, as she ultimately massacres scores of innocents during her siege of King's Landing at the end of "Game of Thrones." So what about non-Targaryen incest in the franchise — and what about Daenerys? Does she dabble?

Daenerys, for her part, does more than dabble ... but to be absolutely fair to her, it's kind of an accident that she gets down and dirty with a family member. When she meets presumed Stark bastard Jon Snow (Kit Harington) in the show's penultimate season, Daenerys thinks he's just a handsome boy without a real family name. As it turns out, he's the legitimate son of Rhaegar Targaryen and Lyanna Stark, the late sister of Jon's father figure Ned (Sean Bean), which makes Jon her nephew. It should be noted, though, that when Daenerys does find out that she and Jon share genetic material, she still wants to pursue things and isn't thrilled when Jon declines romantic overtures from his aunt. (That Targaryen blood really is a force to be reckoned with.)

At the end of the day, though, the most famous incestuous couple in Westeros is undoubtedly Cersei Lannister (Lena Headey) and her twin brother, Jaime (Nikolaj Coster-Waldau). These two are particularly into the custom; not only are their three bastard children the presumptive heirs to the throne of King Robert Baratheon (Mark Addy), Cersei's dark-haired husband — all three kids are conspicuously blonde — but "Game of Thrones" begins with Jaime trying to kill a different child who catches them in the act. Cersei and Jaime keep trying to put a stop to their dirty deeds, but as the show comes to a close, the two find their way back to each other and die holding each other as they're crushed by the falling Red Keep, killed by another family-lover — Daenerys — as she levels King's Landing. At least that part's sort of poetic, in a way.

"Game of Thrones" and "House of the Dragon" are both streaming on Max now.