House Nymeros Martell of Sunspear

Before Dorne existed as a realm, Morgan Martell was just an Andal adventurer who put down roots between the mouth of the Greenblood and the Broken Arm. He beat back the First Men holding that stony coast and claimed a strip of land fifty leagues long, though for generations the Martells stayed cautious vassals of the small river-kings along the Greenblood.

Their fortunes changed with a fleet from across the sea. The Rhoynar warrior queen Nymeria arrived with ten thousand ships fleeing Valyria and married Lord Mors Martell; together they broke the other Dornish lords and sent their kings to the Wall. That is why Dorne was the last of the realms to take shape, and why it kept customs no other part of Westeros did: inheritance passes to the firstborn regardless of sex, and its rulers are called princes, not kings.

Not every Rhoynar gave up worship of Mother Rhoyne when they took the Faith of the Seven. Some kept living on the river itself, on barges, and came to be called the Orphans of the Greenblood, though they remained subjects of House Martell all the same.

When Aegon the Conqueror reached Dorne after subduing the rest of Westeros, his army bled out in a desert where dragons counted for little. Aegon decided the land wasn't worth the cost of taking it and let the Martells keep ruling as sovereign princes outside the Iron Throne's reach. No other corner of the Seven Kingdoms managed that, and Dorne held onto its independence for two hundred years.

In 110 AC the Martells sided with the Kingdom of the Three Daughters against Prince Daemon Targaryen at the Stepstones, and King Viserys I even weighed marrying his daughter Rhaenyra to the Prince of Dorne as a way to finally bring all seven kingdoms under one crown. The marriage never happened.

Around 150 AC, Daeron I conquered Dorne, though the occupation didn't last. The lasting union with the Iron Throne came under Daeron II, who married the Dornish princess Myriah while his own sister Daenerys married the reigning Prince Maron Nymeros Martell. It was for her that Maron built the Water Gardens. Dorne has answered to the Iron Throne ever since, though its rulers still go by the title of prince.

The Martells took it badly when Rhaegar Targaryen crowned Lyanna Stark queen of love and beauty at Harrenhal, humiliating his own wife, Princess Elia Martell. Even so, once war broke out against House Baratheon, they stayed loyal to King Aerys II: Elia and her children were in the Red Keep, effectively as hostages.

Dorne supplied a quarter of the royal troops at the Battle of the Trident, and many of those soldiers died there, including Prince Lewyn Martell of the Kingsguard. When King's Landing fell soon after, two knights in Tywin Lannister's service, Gregor Clegane and Amory Lorch, killed Elia and her children during the sack of the city.

Prince Oberyn Martell wanted to keep fighting in Viserys Targaryen's name, but diplomacy between his brother Doran and the Hand of the King, Jon Arryn, kept Dorne from taking up arms again. House Martell ended up swearing loyalty to Robert Baratheon, same as everyone else.

That didn't erase the resentment. With Cersei Lannister now queen, the Martells spent years carrying their anger over what had happened to Elia with no one to collect it from, and chose to keep their distance from the other great houses, dealing with the Free Cities instead of getting tangled up in the affairs of Westeros.

When war breaks out after Robert's death, Dorne doesn't move. King Joffrey demands that Doran Martell and his children swear their loyalty, and at the war council in Riverrun, when Robb Stark is proclaimed King in the North, Ser Marq Piper bets the Dornish will end up backing Renly Baratheon.

They don't. Months later, Tyrion Lannister negotiates a match with Doran in person: Princess Myrcella Baratheon will marry Trystane, the younger son of the Prince of Dorne. It's how House Martell secures itself a seat at the table without declaring for any king at all.

It's Oberyn Martell, not Doran, who travels to King's Landing to take the seat on the small council promised as part of the Myrcella-Trystane match. The moment he arrives, he demands justice for Elia and for what Gregor Clegane did to her during the rebellion, nearly twenty years earlier.

Oberyn sits as a judge, alongside Lord Tywin Lannister and Lord Mace Tyrell, at Tyrion Lannister's trial for Joffrey's death. When Tyrion demands trial by combat, Oberyn steps up as his champion, finally getting his chance to face Gregor Clegane directly. He dies in that fight.

Oberyn's death leaves Doran with no room to wait. He leaves the Water Gardens for Sunspear, and once there has his own nieces, the Sand Snakes, arrested before the Dornish smallfolk, who are baying for war against the Lannisters, get out of hand.

His daughter Arianne doesn't share her father's caution. With help from Ser Arys Oakheart and Gerold Dayne, she tries to crown Myrcella Baratheon queen, but Doran sends an armed patrol that cuts the plot short. In the scuffle, Darkstar wounds Myrcella's face, and Arianne ends up locked up by her own father.

Balon Swann arrives at Sunspear with Gregor Clegane's skull and an invitation for Trystane Martell to travel to King's Landing by land. Doran agrees, but tells his nieces something he won't say in public: he suspects Queen Regent Cersei Lannister wants bandits to kill Trystane along the way.

From there, Doran moves the Sand Snakes like pieces on a board. He sends Obara with Ser Balon to track down Gerold Dayne, puts Nymeria in the small council seat that was meant for Trystane, and sends Tyene, disguised as a septa, to win the High Sparrow's trust.