[Dorne — Locations]
Jaime and Bronn travel to Dorne to bring Myrcella back. They encounter the Sand Snakes , and arrested by Martell guards. They settle the matter with Prince Doran and depart from Dorne. Jaime tells Myrcella the truth of her parentage, and suddenly she dies , poisoned by the Sand Snakes.
As a result, House Targaryen gained the support of the largely intact forces of the Reach , Dorne , and the Iron Islands . After the recent events of her invasion of Westeros, Daenerys's army had already taken several heavy blows. Yara's Ironborn fleet was destroyed by her uncle, Euron Greyjoy . The Sand Snakes, along with Yara, were captured by Euron, effectively knocking Dorne out of the war. Jaime Lannister then led an army into the Reach to sack Highgarden , also knocking House Tyrell out of the war. The Unsullied took moderate casualties at the Fall of Casterly Rock , which was likewise the case with the Dothraki at the Battle of the Goldroad . When Jon Snow , King in the North, sought an alliance with Daenerys for her help in defeating the Army of the Dead threatening all of humanity, he initially refused her condition that he bend the knee as he did not know her yet. However, when Daenerys came to rescue Jon's party Beyond the Wall and the Night King managed to kill Viserion with an ice spear, upon which Daenerys vowed to fight the Night King at Jon's side, Jon bent the knee to Daenerys as queen and agreed to pledge his Northern forces to her. The Night King reanimated Viserion as a wight , leaving Drogon and Rhaegal as Daenerys's living dragons.
The Martell words are "Unbowed, Unbent, Unbroken" - referring to their history, in which they have never been successfully conquered by outsiders. This makes them unique among all of the Great Houses. During Aegon's Conquest (three centuries before the War of the Five Kings), Dorne was the only region of the Seven Kingdoms to successfully resist the Targaryens and their dragons . Realizing that large armies could not stand against dragons (as seen at the Field of Fire ), nor large castles (as seen at the Burning of Harrenhal ), the Dornish instead resorted to guerrilla warfare, ambushing Targaryen soldiers and harassing their supply lines as soon as their dragons moved on to the next castle, then disappearing back into the harsh deserts when the dragons returned. The Dornish armies took advantage of Dorne's arid climate, which helped them to adopt attrition warfare against the invading Targaryens, as the arid climate and harsh wastelands of Dorne cannot easily support large invading armies. Losing many men due to attrition, ultimately even Aegon the Conqueror decided to withdraw from Dorne, to focus on reining in the other six newly conquered kingdoms.
House Martell and Dorne have never been successfully conquered. Over a century and a half after the Targaryen Conquest of the rest of Westeros, they were invaded again by King Daeron I Targaryen , the Young Dragon. A military genius, his Conquest of Dorne actually succeeded - on the battlefield. But the initial conquest was followed by a four year long Dornish insurgency, in which occupying troops were again bled through ambush and guerrilla tactics. Lyonel Tyrell , the steward that Daeron I put in charge of Dorne, was then assassinated, and all of Dorne rose up in open rebellion. Daeron I himself was killed attempting to put down the insurrection, and after only four short years House Martell once again ruled an independent Dorne.
A few decades later (a little over a century before the War of the Five Kings), King Daeron II the Good managed to finally unite Dorne with the Iron Throne - not through conquest, but by voluntary marriage-alliance on equal terms. Daeron II married the sister of the Prince of Dorne, and the Prince of Dorne married Daeron II's sister . This special, semi-autonomous status allowed Dorne to retain several special privileges, such as the Martells continuing to style themselves as "Prince" or "Princess" instead of "Lord Paramount" and continuing their practice of gender-blind primogeniture. This union did cause several political tensions at the royal court between Daeron II's pro-Martell faction and anti-Martell lords (from the Reach, the Stormlands, and the Dornish Marches ), eventually leading to the Blackfyre Rebellion .
Generations later, King Aerys II Targaryen (later known as "the Mad King") had no daughters, so he sought a suitable bride for his son Crown Prince Rhaegar Targaryen from outside of the family. Aerys II chose to snub the offer of Tywin Lannister , his own trusted Hand of the King and dutiful servant, that Rhaegar marry his own young daughter Cersei . Instead, a match was arranged with the then-current Princess of Dorne to wed her daughter Elia Martell to Rhaegar.
House Martell was originally a tiny, obscure noble house of Dorne back when the peninsula was home to numerous small, warring states, approximately one thousand years ago. The Rhoynar , refugees from a war against Valyria on the eastern continent, fled to Westeros led by their warrior-queen Nymeria, where they made landfall in Dorne and allied with Lord Mors Martell. After a brief war, Mors named himself the ruler of the unified Kingdom of Dorne, adopting the title "Prince" rather than "King" in Rhoynish fashion. Mors married Nymeria, uniting the bloodlines of the Rhoynar with the native First Men and Andals. As a result, the full name of the family is actually "House Nymeros Martell", with "Nymeros" signifying "of Nymeria". For example, Oberyn's full name is given as "Oberyn Nymeros Martell". However, even the Martells themselves do not usually use the full name, with the inclusion of "Nymeros", except on very formal occasions.
When Aegon I Targaryen invaded Westeros, he conquered six of the seven kingdoms extant at that time, but the Dornish refused to give open battle where Aegon could destroy them with his dragons , instead resorting to hit-and-run attacks which severely damaged his army through attrition. Aegon agreed to leave Dorne to its own devices after trying to conquer it again during the First Dornish War of 4 AC to 13 AC. However, the Dornish once again prevailed and the Martells managed to kill Aegon's wife, Rhaenys, before forcing the Conqueror to agree to peace on their terms. Aegon never tried conquering Dorne again.
A century and a half later, Dorne was briefly occupied by the armies of King Daeron I, but overthrew them in a bloody rebellion. Eventually, roughly a century before the events of the series, Dorne joined the Seven Kingdoms through a peaceful marriage alliance. House Martell's motto, "Unbowed, Unbent, Unbroken", directly references the fact that they were never conquered by outsiders. Because they came under the authority of the Iron Throne through marriage instead of the sword, House Martell and the other Dornish houses continue to practice absolute primogeniture, in which the eldest child is the designated heir, regardless of whether they are male or female. Another major difference is that the rulers of Dorne are styled ruling Princes (or ruling Princesses) instead of Lords Paramount. At the time of the beginning of the narrative the current head of House Martell is the aging Prince Doran. His daughter and eldest child is Arianne Martell: despite being female, she has been actively groomed to succeed her father, as are eldest daughters all over Dorne. In his old age and infirmity (though he retains his wits) Doran has semi-retired, delegating most of the day-to-day governance of Dorne to Arianne.
In the second novel, Varys reports Tyrion that Prince Doran Martell has called his banners, and there are rumors that he intends to join Renly Baratheon (Renly tells Catelyn Stark the same thing). Knowing that an alliance between Renly and Dorne will be disastrous to the Lannisters, Tyrion take steps to prevent it by offering Prince Doran to marry Myrcella to Trystane, his sister's killer , a seat at the Small Council , and some castles on the Marches. Despite Cersei's protests, Tyrion sends Myrcella to Dorne as a token of good faith. The Martells stay neutral throughout the war, although it is unclear whether the reason is Tyrion's offer, or the Martells bide their time.