Nós não sabemos ... porque os Maesters não nos contaram.
There are none who can say with certain knowledge when the world began, yet this has not stopped many maesters and learned men from seeking the answer. Is it forty thousand years old, as some hold, or perhaps a number as large as five hundred thousand—or even more? It is not written in any book that we know, for in the first age of the world, the Dawn Age, men were not lettered.
- The World of Ice and Fire, The Dawn Age
São milhares de anos de história antes da Conquista de Aegon, mas o mensageiro nunca conta por que eles escolheram a conquista, só que eles fizeram
.The maesters of the Citadel who keep the histories of Westeros have used Aegon's Conquest as their touchstone for the past three hundred years. Births, deaths, battles, and other events are dated either AC (After the Conquest) or BC (Before the Conquest).
- The World of Ice and Fire, The Conquest
Além disso, a informação pode estar lá, nós, como leitores, não recebemos "acesso"
One issue that plagues all studies of the ancient records is how differently the varied cultures reckon days and seasons and years. Archmaester Walgram's great work, The Reckoning of Time, delves deeply into this problem, but there is little consensus on what the dates we have actually mean in our own reckoning.
- The World of Ice and Fire, Other Lands
Se pudéssemos colocar as mãos em uma cópia do O reconhecimento do tempo , poderíamos ter uma resposta muito melhor ...
Para a explicação da passagem física desses anos, ver: O que é um" ano "em Westeros?
A segunda resposta fornece as informações mais relevantes da IMO.