"Valyria's Last Scion: House Targaryen" is the first chapter of Conquest & Rebellion: An Animated History of the Seven Kingdoms, a special feature from Game of Thrones: The Complete Seventh Season. It is narrated by Harry Lloyd as Viserys Targaryen.
Viserys Targaryen: This world wasn't always so small and petty. Thousands of years ago, while the rest of men prayed to gods, the Valyrians became them. Through magic or sheer will, they mastered the greatest creatures in history. A horse grants man dominion over the land, a ship over the sea. But dragons gave us the sky, and everything and everyone beneath it.
At its height, my ancestors ruled the Known World. Whatever parts we didn't weren't worth knowing. Our capital of Valyria shamed the magnificent cities of the east, for hammers and chisels were no match for dragonfire and sorcery. It was a city and an empire built to last until the end of time. It didn't.
Four hundred years ago, the Doom fell on Valyria. Mountains cracked open like eggs. Lakes and rivers boiled. Fountains of fire, ash, and smoke spewed from the ground, so high and so hot that even dragons burned in flight. The land splintered, and the angry sea rushed in. In hours, the greatest city in history became history.
But my ancestors didn't burn or drown with the rest of their race. Twelve years before the Doom, despite the sneers of his rivals, Aenar Targaryen abandoned the capital with his family. Legends claim that his daughter foresaw the destruction of the city in a dream. More likely, Aenar met with some mishap at court and chose exile over execution. He and House Targaryen slinked away to a dreary, remote, godforsaken island. Forsaken no longer. With arts now lost to the world, we transformed a tiny outpost into Dragonstone, a fortress fit for the last Dragonlords.
Then Aenar's descendants settled into it like a tomb for their lost homeland. Until Aegon. When he looked east, he saw the past: old, tired, dead. But when he looked west, he saw the future: gold in the ground, gold in the fields, and no dragons in the sky but his. He and his sisters, Rhaenys and Visenya, flew over the great continent, ostensibly visitors to a strange land. But when Aegon returned, he ordered construction of a massive table carved in the shape of Westeros, with all the notable rivers and mountains that they had seen. A personal map of the Seven Kingdoms, then ruled by seven squabbling families.
House Durrandon held the Stormlands from their seat at Storm's End, due south of Dragonstone. House Hoare of the Iron Islands had also conquered and enslaved the Riverlands, and ruled them from Harrenhal, a monstrous castle rising on the shore of the Gods Eye. House Stark held the frozen wasteland of the North, the oldest, largest, and emptiest of the kingdoms. House Lannister held the Westerlands, the wealthiest kingdom thanks to their gold mines. House Gardener held the Reach, the second wealthiest kingdom thanks to their crops. House Arryn held the Vale, or rather the Vale held them. The mountains were impassable except through the Bloody Gate, which had never been taken. House Martell held the deserts of Dorne, probably because no one else wanted them. Together, the Seven Kingdoms made Westeros, a realm that wasn't yet a realm, ruled by great families who didn't know what greatness was. Aegon would teach them.
- The video doesn't specify this, but the Targaryens stayed isolated on Dragonstone for about one century after the Doom but before Aegon I invaded mainland Westeros. In the meantime, the Valyrians' former empire across the rest of Essos fell apart in the Century of Blood.
- Seven generations of Targaryens lived on Dragonstone before the War of Conquest: counting Aenar Targaryen as the first, and Aegon I and his sisters as the seventh.
- The Valyrians established an outpost on Dragonstone about two centuries before Aenar Targaryen moved his household there. It was an ideal location for controlling sea trade along the east coast of Westeros, and to trade with the local kings of Westeros - who were willing to pay exorbitantly for Valyrian steel weapons.
- In the novels, Tyrion ponders why the Valyrians stopped at Dragonstone and didn't continue to conquer the rest of Westeros: the dragonlords were still at the height of their power, and Westeros was divided into seven rival kingdoms (even the later Aegon I, with a small fraction of the Valyrians' forces, was able to successfully conquer them). Season 7 of the TV series strongly implies that the reason they came was for the massive dragonglass mine beneath the island, which was so valuable it's all they cared about.
- Aenar Targaryen actually brought five dragons to Dragonstone island: one of them was Balerion, but the other four later died through as-yet undescribed circumstances (possibly just old age, as other sources say they didn't fight each other). These other four left behind eggs, however, from which later hatched Meraxes and Vhagar, so the Targaryens had three dragons by Aegon I's time.
- Aegon I Targaryen
- Aenar Targaryen
- Daenys Targaryen (indirectly mentioned)
- Rhaenys Targaryen
- Visenya Targaryen
- The Known World
- Narrow Sea
- House Arryn (sigil)
- House Baratheon (sigil)
- House Gardener (sigil)
- House Hoare (sigil)
- House Lannister (sigil)
- House Martell (sigil)
- House Stark (sigil)
- House Targaryen