Her name is pronounced "Ruh-near-uh". While this may seem odd, the official pronunciation guide developed for the cast and crew of the TV series states that "Daenerys" is pronounced "Duh-NAIR-iss", so apparently the "ae" syllable in George R.R. Martin's writing is somehow meant to represent a short "u" sound as in "put".
Rhaenyra was a Princess of the Targaryen dynasty. She was the half-sister of Aegon II Targaryen, and the mother of Aegon III Targaryen. Her son Aegon III was himself the father of King Baelor Targaryen.
Touring the Great Sept of Baelor in King's Landing, King Joffrey Baratheon explains to Margaery Tyrell that Rhaenyra Targaryen was eaten by her brother's dragon while her son was forced to watch. Joffrey points out the crypts where what little is left of her is kept.
In the books
In the A Song of Ice and Fire novels, Rhaenyra was the daughter and eldest surviving child of King Viserys I. Rhaenyra was the only woman of the Targaryen dynasty who ever tried to rule the Seven Kingdoms as Queen Regnant in her own right. Rhaenyra was raised her entire life as the heir apparent, and this made her quite pampered and arrogant. She was married twice, having three sons by her first husband and two by her second husband.
However, after her mother died her father remarried and had several sons by his second wife. Even so, Viserys I still publicly expected his daughter to succeed him, and when he died, his official will even stated so. Rhaenyra's younger half-brother Aegon, however, challenged her claim, citing that the normal inheritance laws of the Andals in the Seven Kingdoms (which had been united by House Targaryen only 129 years before by Aegon the Conqueror) followed male-preference primogeniture, meaning that a younger son would rightfully inherit before an older daughter. Rhaenyra had been raised as the heir apparent for years and commanded the loyalty of an inner circle of noble families very close to the crown. In defiance, her half-brother had himself crowned in King's Landing as Aegon II, and rallied to his side those noble Houses who did not enjoy royal favor during the reign of her father.
This began a devastating civil war that tore apart the Seven Kingdoms, which later became known as The Dance of the Dragons, as Targaryen fought Targaryen and dragon fought dragon. The civil war lasted three years. Most of the Targaryen dragons were used up in the civil war, as the only thing that can easily kill a dragon is another dragon. The civil war lasted for three years, during which all three of Rhaenyra's sons by her first husband were killed. At some point Rhaenyra herself was captured by Aegon II's forces, and in a public execution was fed to her half-brother Aegon II's dragon, while her son was forced to watch.
Rhaenyra's supporters continued to fight on in the name of her two surviving sons, however, and eventually triumphed. Through uncertain circumstances Aegon II died without male heirs, and peace was achieved when Rhaenyra's eldest surviving son was crowned as Aegon III. He was the son who had been forced to watch his mother consumed by a dragon, and he developed a deep hatred and fear of the creatures. So many dragons had died in the war that they couldn't maintain a stable breeding population, and the few survivors became inbred an sickly. The last Targaryen dragons - the last dragons in the known world - died during the reign of Aegon III, earning him the sobriquet "Aegon the Dragonbane". Aegon III married Aegon II's surviving daughter to re-unite the factions from the war, though many cadet branches and relatives of House Targaryen had been killed in the war. Aegon III ruled well, and both his sons (Daeron I and Baelor I) became king after him, but each died childless. Therefore, the throne later passed to Rhaenyra's youngest son, Viserys II, who served as Hand of the King under his nephews for many years. Viserys II was the father of Aegon IV and grandfather of Daeron II, and Daeron II was himself the grandfather of Aerion Brightfame, Aegon V "the Unlikely", and Maester Aemon.
After the Dance of the Dragons, House Targaryen revised the royal succession laws to follow a modified and extremely strict version of male-preference primogeniture, in which female heirs are put behind all possible male ones. For example, under the succession laws of most Andal nobles in Westeros, a lord's daughter will succeed before his own younger brother, but under the new Targaryen royal succession laws, a lord's younger brother will inherit before the lord's daughter. Before Rhaenyra, the first five generations of Targaryens (Aegon I, his sons Aenys I and Maegor I, Aenys I's son Jaehaerys I, his son, and Viserys I) had simply never produced a firstborn daughter before, so this did not retroactively remove an older female branch from the line of succession.
During her life, Rhaenyra styled herself "Rhaenyra of House Targaryen, First of Her Name", but subsequent histories do not refer to her as "Rhaenyra I". Many felt that because Rhaenyra's own son Aegon III ended up succeeding to the throne, the dynastic claim of her faction was vindicated. However, at this point House Targaryen wanted to enforce the new strict male-preference primogeniture laws, under which the deceased Rhaenyra would never have inherited in the first place. Thus, even her own son could not retroactively consider his mother to have been the rightful ruler during the civil war. If her half-brother was retroactively established as not the lawful heir, Rhaenyra's son would have been crowned under the royal name "Aegon II" not "Aegon III", to reinforce that his uncle had not been the lawful heir. Because he couldn't do this and enforce the new strict male-preference primogeniture laws, her son had to take the name "Aegon III" and officially declare that his mother had only been a rival claimant, not the lawful heir.
It is because of Rhaenyra and the Dance of the Dragons, and the stricter male-preference royal inheritance laws that House Targaryen embraced as a result, that there has never been a ruling Queen on the Iron Throne, at any point in the subsequent 170 years between the Dance and the War of the Five Kings. Any subsequent female monarch of the name "Rhaenyra" would have to be styled "Rhaenyra I", not "Rhaenyra II", though the Targaryens just avoided the issue by never naming one of their daughters "Rhaenyra" again.
Rhaenyra may have formed her own rival Kingsguard, which may have been known as a Queensgard. Daenerys Targaryen later forms her own "Queensgard", but it isn't clear whether this is a term Daenerys made up, or if it is the proper term for the Kinsguard under a female monarch. It is known that just as Targaryen fought Targaryen and dragon fought dragon in the civil war, the Kingsguard was split, with different members joining both sides. Lord Commander Criston Cole of the Kingsguard had chosen to declare her half-brother Aegon II king, and thereafter became known as "the Kingmaker", but he died during the civil war.
Rhaenyra Targaryen and the Dance of the Dragons are going to be the subject of an upcoming prequel novella by author George R.R. Martin, titled The Princess and the Queen.
The succession dispute and civil war between Rhaenyra and Aegon II is analogous to the Anarchy in England during the early twelfth century, during which King Henry I's only surviving heir was his daughter Matilda. Like Rhaenyra, Matilda was quite pampered and arrogant (as a result of expecting to be heir and being the widow of the Holy Roman Emperor), though she hadn't been raised as the heir apparent her whole life (Henry I's son died later in the White Ship disaster). Matilda was challenged by her cousin Stephen of Blois, who was from a junior branch of the royal family but nonetheless usurped the throne by rushing to the capital to be crowned king. In the cases of both Rhaenyra/Aegon II and Matilda/Stephen, the resulting civil war wasn't really concerned with who the lawful heir was under different succession rights, but was truly a struggle between two major factions of nobles which had developed: those who currently enjoyed royal favor (under Rhaenyra and Matilda) and those who had not previously enjoyed royal favor (the supporters of Aegon II and Stephen). In both cases, the rival male claimant is historically considered the lawful ruler (Aegon II and Stephen), but the son of the female claimant (Rhaenyra and Matilda) ended up ruling after the male claimant's son had died (the succession of Aegon III and Henry II Plantagenet).
- Rhaenyra Targaryen at A Wiki of Ice and Fire (spoilers from the books)
Kings of the Seven Kingdoms
Aegon I, the Conqueror · Aenys I · Maegor I, the Cruel · Jaehaerys I, the Conciliator · Viserys I · Aegon II · Aegon III, the Dragonbane · Daeron I, the Young Dragon · Baelor I, the Blessed · Viserys II · Aegon IV, the Unworthy · Daeron II, the Good · Aerys I · Maekar I · Aegon V, the Unlikely · Aerys II, the Mad