The Lhazareen
Since the deep past
Shepherds in the hills between the grass and the bay, worshipping a Great Shepherd, raided by everyone.
The fuller tale
The Dothraki call them the Lamb Men and mean it as contempt: a peaceful, flat-faced, copper-skinned people who keep sheep and goats in the hills above Slaver's Bay and do not fight back well. Their villages are the natural stopping place for any khalasar riding to the bay to sell captives, which is a geography that has decided their entire history.
They are one of the few peoples in this chronicle who have never conquered anybody, never built an empire, and are still there ÔÇö which, measured against Sarnor or Ghis or Valyria, is not the worst record on the map.
Souls under this banner ÔÇö the chronicleÔÇÖs own reckoning, never a census; Westeros keeps none. See the note in the timeline.
The ground they held
 See the world in 1 AC on the timeline What became of it  if an ending is written, it is here. Spoilers.
The chronicle records no ending here ÔÇö or none the maesters have set down.