Win or Die
Dragons are native to the continent of Essos, and it is said the first dragons came from the east, from the Shadow Lands beyond Asshai and the islands of the Jade Sea.
Dragons populated most of the known world in ages past, and ancient dragon bones have been found as far north as Ib and as south as the jungles of Sothoryos. The yellow emperor Chai Duq of Yi Ti is said to have kept a dragon at his court.
In Barth's Unnatural History, the septon seems to have considered several legends regarding the origins of dragons. The Valyrians claimed that dragons sprang forth from the Fourteen Flames, a ring of volcanoes on the Valyrian peninsula. Meanwhile, in Qarth, tales state dragons came from a second moon in the sky, which was scalded by the sun and cracked like an egg, and a million dragons poured forth. In Asshai, however, there are many tales – some impossibly ancient – which claim that dragons first appeared on the Shadow Lands and a people so ancient they have no name first tamed these dragons, brought them to Valyria and taught the Valyrians their arts before departing from the annals of history. Barth would put forth the theory that dragons were created by the bloodmages of the Freehold, using wyvern stock.
Regardless of their origin, the Valyrians mastered the art of raising dragons and used them as weapons of war to carve out a massive empire. According to legend, a dragon may be tamed by sounding a dragon horn.
Dragons are also said to have once roosted on Battle Isle until the first Hightower put an end to them.
After the Doom of Valyria, the only dragons known to have survived were five dragons on Dragonstone. The dragons belonged to House Targaryen, who had brought them from Valyria when they went into exile. Four of these dragons eventually died on Dragonstone, leaving only Balerion. However, the other dragons left eggs behind, and from these hatched Vhagar and Meraxes.
House Targaryen used Balerion, Vhagar, and Meraxes in their Wars of Conquest against the Seven Kingdoms. They were instrumental in the burning of Harrenhal and the Field of Fire, and the threat of dragons led to the submissions of Torrhen Stark and Sharra Arryn. Dragons were also used in the First Dornish War, which caused the death of Meraxes at the Hellholt in 10 AC. The valuable golden coin of the Iron Throne became known as a dragon.
Dragon fought dragon in the Battle Beneath the Gods Eye, resulting in the death of the dragon Quicksilver in 43 AC.
Over the course of one hundred and fifty years the Targaryens rode their dragons as a symbol of their power. King Jaehaerys I Targaryen took six dragons with him to the north to visit the Warden of the North. These included Jaehaerys on Vermithor, Queen Alysanne on Silverwing, and four other currently-unknown dragons.
Balerion finally died of old age in 94 AC, late in the reign of Jaehaerys I. Jaehaerys's grandson and eventual successor Viserys I was Balerion's rider at the time of its death. This left Vhagar as the largest living dragon, and by 129 AC she was approaching Balerion's size.
Many dragons were hatched after Aegon's Conquest. By 129 AC, on the eve of civil war between Rhaenyra and Aegon II, there were twenty living dragons. The largest and oldest dragons were Vhagar, Vermithor, Silverwing, Dreamfyre, Meleys, Caraxes, and Syrax. Younger dragons still large enough to be ridden to war were Seasmoke, Sunfyre, Tessarion, Vermax, Arrax, Tyraxes, and Moondancer. Stormcloud, Morghul, and Shrykos were hatchlings not yet big enough to ride.
There were also three wild dragons living on Dragonstone which had never been successfully claimed by any rider: Grey Ghost, Sheepstealer, and the Cannibal. Sheepstealer hatched when Jaehaerys I was still young, and the Cannibal was even older (none knew for certain when it had hatched), and thus they were also quite large by the time of the Dance of the Dragons, while Grey Ghost was a younger and smaller beast. Not every hatchling lived to maturity, however, as seen with Rhaena of Pentos, whose hatchling only lived a matter of hours.
By the end of the reign of King Viserys I Targaryen, twenty dragons were alive. The majority of these died during the civil war called the Dance of the Dragons, which began in 129 AC and would last until mid 131 AC. Archmaester Marwyn, however, holds that the order of maesters, with their secret goal to suppress magic, was responsible for the extinction of dragons.
By the end of the Dance in 131 AC, only four dragons remained alive: Sheepstealer, the Cannibal, and Silverwing, who had been born years before the war, and the dragon Morning, which had hatched during the war. There were still many dragon eggs left after the war, and at least one of those hatched. The last dragon was a stunted, sick and misshapen thing, and she died young, in 153 AC, during the reign of King Aegon III Targaryen, the Dragonbane. She had been a green female, small with withered wings. She laid a clutch of five eggs, which never hatched.
The Targaryens also had a collection of nineteen dragons skulls of various sizes and ages that they displayed on the walls of the throne room in the Red Keep. Some of these were thousands of years old.
After their extinction, the only remnants of dragons that remained were their skulls and the eggs, some of which were petrified. The eggs were highly valuable, for their beauty and exotic nature. According to Ser Arlan of Pennytree, the summers became shorter after the last dragon died, and the winters longer and crueler.