Volantis

The eldest daughter of Valyria, which tried to inherit the Freehold and settled for five slaves to every free man.

The fuller tale

Volantis was the first and greatest of Valyria's colonies, at the mouth of the Rhoyne behind the Black Wall the dragonlords raised, and when the Doom came it declared itself the Freehold's heir. For two generations it made that stick: Myr and Lys were taken, and Volantene armies went as far as Valyria's ashes.

It overreached, as the first city to move usually does. A coalition of the other Free Cities, Pentoshi gold and a Westerosi sellsword prince broke the attempt, and Volantis has spent the three centuries since being enormous, wealthy and no longer in charge of anything but itself.

Five slaves for every free man is the figure the city itself quotes, and the tiger-and-elephant argument that runs its politics is an argument about which of them should be sent to war.

The ground they held

 See the world in 298 AC 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.