The history of Westeros appears to have been going on at least 12,000 years, give or take a few hundred years. Beginning with the time that the First Men appeared with their bronze weapons and their relatively domestic horses.
As always there was a war between them and the Children of the Forest, a diminutive race who lived in harmony with nature and employed powerful magic. However this was resolved when the Pact of the Isle of Faces was created with the First Men taking control of the open lands and the Children remaining in the forests, allowing peace between them for 4,000 years.
Unfortunately, The Pact was weakened after four thousand years by the emergence of the Others, an enigmatic race from the furthermost north, who swept south into Westeros and caused great death and destruction, bringing about a night that lasted a generation and a winter that lasted decades.
Then, as it always happens, the Andals came (roughly 6,000 years ago) and they brought deadly iron weapons, and a brand new religion and with that the slaughtering of children and even more despair.
It is believed that the six southern kingdoms during that time fell to the Andals while the North as we know was not overrun.
Over time six great and powerful kingdoms were forged across Westeros: the Kingdom of the North, the Kingdom of the Iron Islands, the Kingdom of Vale and Sky, the Kingdom of the Rock, the Kingdom of the Storm Kings and the Kingdom of the Reach. A seventh kingdom—that of the Riverlands—was repeatedly conquered by its neighbors and eventually destroyed altogether, while the small desert kingdoms in the far south of Westeros were divided by constant war.
Five centuries later, the expanding Valyrian Freehold had reached the east coast of the Narrow Sea and established links with Westeros, using the island of Dragonstone as a trading port. A century later the Valyrian Freehold was destroyed by a cataclysmic disaster of volcanic eruptions and earthquakes, known as The Doom of Valyria, and resulting in a smoking unstable wasteland of ghosts and legends. The Valyrian family that controlled Dragonstone, the Targaryens, spent a further century in preparing their forces, and then launched a devastating invasion of Westeros under Aegon the Conqueror. Although their forces were small, they had with them the last three dragons in the western world and they were able to use these to overtake the continent. Six of the Seven Kingdoms were conquered in this initial war, but Dorne resisted so fiercely that Aegon agreed to let them remain independent. The Targaryens adopted the native Faith of the Seven (although they still married brother to sister in the ancient Valyrian tradition in defiance of the Faith’s teachings) and Westerosi customs, and within a few decades had crushed all resistance to their rule. Dorne was eventually absorbed through marriage-alliance. The last dragons died out a century and a half into the Targaryen rule, but by this time they had become the ruling power on the continent and their rule was not challenged.
It is said that after the Andals, things in the world began to settle, and became more strictly recorded creating the accepted history.
The oldest histories we have were written after the Andals came to Westeros. The First Men only left us runes on rocks, so everything we think we know about the Age of Heroes and the Dawn Age and the Long Night comes from accounts set down by septons thousands of years later.” (A Feast for Crows)
It should be noted that since the oldest parts of the history were written after the Andals, that everything known before than is merely rumor and hearsay. Legends and stories, and oral histories are what make up the tumultuous years before.
This opens the history up to questions, which does happen with Samwell, who is the first to begin questions the truth behind what is claimed to be history. While pre-Andal history is more than murky and questionable, even the post-Andal world is uncertain when it comes to certain dates and events.
Another problem with the complicated history is that much of the popular history comes from oral stories passed around from troubadours, to travelers, to gossipers all over the world. Did the singers take Aegon the Unworthy’s innuendos about his siblings the Dragonknight and Naerys and turn them into one of the great romances of the Seven Kingdoms? It is probable. While this form of storyteller is quite magical and attention catching, it doesn’t help that things are often exaggerated, and misunderstood which in turn creates a new story for history.
While there is no answer, yet, about why all of a sudden the commonly accepted history is now being questioned, I think we can reasonably assume that this will come up eventually and probably affect everything we have come to accept about the setting of A Song of Ice and Fire.
