|The title of this article is conjecture based on information revealed in the A Song of Ice and Fire novels or related material and may be subject to change.
- "When Aegon's heir wed his daughter to his son, the Faith could brook such abomination no longer. The High Septon led the denunciation of the Targaryens, and all over Westeros the Faith Militant took up its swords against the dynasty and its supporters."
- ―The High Sparrow
Princess Rhaena Targaryen is an unseen character in Game of Thrones. She is not expected to appear in the show, being long dead by the time it begins. Rhaena was a member of House Targaryen and was the eldest daughter and child of King Aenys Targaryen.
Rhaena was wed to her own brother Aegon by her father King Aenys, according to Valyrian custom. The leadership of the Faith of the Seven, who already had strained relations with the crown, condemned this incestuous union, and the Faith Militant revolted against the Targaryens.
In the books
Rhaena was the firstborn child of King Aenys I. Her grandfather, Aegon the Conqueror, maintained a polygamous marriage with both of his sisters: Aenys's mother Rhaenys and Maegor's mother Visenya. Aegon himself always treated Aenys as his heir apparent because he was older than Maegor - though given young Aenys's frailty, there were some who muttered that Maegor should be his heir, given that he was his "firstborn" by Visenya - those who said this were chiefly Visenya herself, and her supporters, though Aegon I would hear none of it.
Thus, the birth of Aenys's own children pushed Maegor even further back in the line of succession, as by the normal laws of Westeros an uncle only inherits after his elder brother's entire bloodline is extinguished. For that matter, as the years passed Maegor failed to produce any heir, and there were fears that he was sterile - causing him to lose supporters, who didn't think it was worth upsetting Aegon I's intended succession for an heir who couldn't continue the family line anyway.
Aegon I was still wary of offending the Faith of the Seven, and promised them that his family's incestuous marriage practices were a relic of the past which they wouldn't continue in the future. To assure him of this, he had Aenys marry Alyssa Velaryon as a political match, who was mother to all of his children. Maegor's mother Visenya didn't give up on her ambitions in court politics, however, pushing for Maegor to one day succeed ahead of Aenys. Thus when Rhaena was born, Visenya urged Aegon I to betroth her to her Maegor, her own half-uncle. Aegon I, however, dismissed the suggestion - both because he didn't want to risk offending the Faith with such an incestuous marriage, and (it is believed) because he had become frustrated with Visenya's constant attempts to usurp Rhaenys's son Aenys with her own.
As she grew up Rhaena became a dragonrider: her mount was Dreamfyre, one of the progeny of the original three Targaryen dragons.
Rhaena was born in 23 AC, and her father announced her marriage to her younger brother Prince Aegon in 41 AC - when she was 18 years old and her brother was 15 years old. No one knows exactly why Aenys launched into such an obvious folly, given how strained his relations with the Faith already were: some suspect that as the Red Keep's construction grew, he began to think on the glorious Targaryen legacy he would leave behind, and thus he gave more focus to "keeping the bloodline pure".
Rhaena and Prince Aegon were making a royal progress through the realm when the Faith Militant uprising struck: they were in the Westerlands at the time, and were besieged in Crakehall castle. Within a few weeks, their father Aenys fled to Dragonstone and died in 42 AC (possibly poisoned by Visenya). Maegor then retook King's Landing using Balerion, and usurped the throne ahead of Rhaena's brother-husband Prince Aegon.
The Lannisters extended Aegon and Rhaena Guest right but would not rise against Maegor, leaving them stranded for some time. It was difficult for Maegor to pursue them due to having to devote much of his attention to campaigns against the Faith Militant in central Westeros.
In 43 AC, Prince Aegon himself rallied an army to rebel against his half-uncle Maegor, riding Aenys's own dragon Quicksilver. They clashed in the great Battle Beneath the God's Eye, but Maegor rode the awesome Balerion, killing both Quicksilver and Aegon. In the intervening years Rhaena had given birth to twin daughters, Aerea and Rhalla, and she fled with them to Fair Isle off the west coast for some time. They were ultimately found, however, and taken captive back to Maegor's court at King's Landing.
By this point Maegor had already entered into three polygamous marriages, but still could not produce a viable heir. Growing increasingly unstable, in 47 AC Maegor forced Rhaena herself to marry him - one of three new "Black Brides" that he wed in a triple ceremony, each of them women of proven fertility (whose husbands he had killed in the war). Mercifully, Rhaena never became pregnant by Maegor - unlike his other brides who bore him monstrously deformed stillbirths. Rhaena was thus technically a Queen Consort of the Seven Kingdoms - though for only a year or two, and the Faith never sanctioned the marriage (she was presumably Aegon's consort when he rose in rebellion against Maegor, but Aegon did not successfully take control of the throne, making her at most the queen of a rival claimant - assuming she ever formally claimed the title).
In 48 AC, however, Maegor's behavior had grown so intolerable that many great lords of the realm had finally had enough and turned against him - even the Tullys, who had fought against Prince Aegon not long before. They rallied behind Rhaena's youngest brother, Jaehaerys I Targaryen, who claimed his right to the throne as Aenys's son. Maegor never totally broke Rhaena: when she heard that Jaehaerys had raised a new, massive rebel army against Maegor, while the castle slept she stole the king's sword Blackfyre, then fled King's Landing flying her dragon Dreamfyre. She then brought Blackfyre to Jaehaerys and joined his cause. All of Maegor's supporters then abandoned him, and he died on the Iron Throne - apparently committing suicide by opening his wrists on its blades, rather than be taken alive.
Rhaena actually outlived Maegor, though no information has been given so far on her subsequent life, or that of her twin daughters. Jaehaerys I apparently claimed the throne by Andal custom of male-preference primogeniture (along with his own sister-wife, Rhaena's younger sister Alysanne. There has been no mention if Rhaena's bloodline through her daughters endured).