The Kingdom of Sarnor

The Tall Men of the northern grass, with chariots and a dozen cities, erased inside a single century.

The fuller tale

Sarnor was old ÔÇö it fought Ghis when Ghis was the world's only empire ÔÇö and it was rich, a confederation of city-kingdoms strung along the rivers of the northern grasslands, famous for scythed chariots and for quarrelling with itself. It never once managed to be one country for longer than a war took.

That was fatal. When the Dothraki came out of the east united and the Sarnori did not, the cities fell one at a time over the course of the Century of Blood: Sathar, Sarys, Gornath, Kasath, Sallosh, and at the last Sarnath the Tall Town. The maps still print the names, followed by the word ruins.

It is the clearest case in this history of a civilisation that was destroyed not because the enemy was stronger but because it could not agree to face it together ÔÇö a lesson Westeros would have several occasions to relearn.

The ground they held

 See the world in 200 BC on the timeline 

What became of it ÔÇö if an ending is written, it is here. Spoilers.

The chronicle records no ending here ÔÇö or none the maesters have set down.