Of the Seven Kingdoms, Dorne alone defied the dragons and kept its freedom. When Aegon the Conqueror and his sisters brought fire and blood to Westeros, six realms bent the knee or were burned into submission, but the Dornishmen would not treat with him at all. The Princess Meria Martell, whom the smallfolk called the Yellow Toad of Dorne, gave the Conqueror's envoys a cold answer: Dorne had no king, and would have no king, and would not fight the dragons but would not yield to them either. So it proved. Aegon's first campaign against the deserts came to little, and it was not until 4 AC, some years after the Conquest was reckoned complete, that the true war began.
The Targaryens found Dorne a poor country for dragons. The Dornish would not gather their strength in the field to be burned; instead they melted into the sands and the passes of the Red Mountains, struck at supply and stragglers, and abandoned their castles rather than hold them. Aegon and his sisters took keep after keep and found them empty. When the dragons flew on, the Dornish crept back and slew whatever garrisons had been left behind. Sunspear, Vaith, the Hellholt, and Yronwood were all put to the torch at one time or another, yet none of it broke the Dornish will. The war became a thing of ambushes and reprisals that bled the Iron Throne for the better part of a decade and gave the crown little in return.
The war's cruelest turn came in 10 AC, when Queen Rhaenys and her dragon Meraxes were brought down over the Hellholt and both were lost. Aegon's grief became the realm's terror, for the years that followed saw the Dragon's Wroth, a campaign of burnings without mercy or object save to punish. Yet even fire had its limits against a foe who would not stand and die. By 13 AC, worn down by years of bloodshed on both sides and with Dornish assassins reaching close enough to touch even the royal family, Aegon at last agreed to a peace. Dorne kept its princes, its laws, and its independence, and would not be joined to the Iron Throne for near two hundred years, until the marriage of Daeron II to Myriah Martell bound the two realms in blood rather than fire.