Humans returned to Dragon Pass around 1250 ST. These were the remnants of the Pure Horse People of Prax. Bands of Pure Horse People and their horses wandered about Dragon Pass, although from the start they favored the hills and valleys in the southwestern part of the Pass.
Orlanthi from the Holy Country began to settle the Pass only 50 years later. The first group were the Colymar, who settled around Clearwine. But starting in 1325, the first of several waves of settlement came from the Holy Country into southern Dragon Pass.
Around 1330 came the first Orlanthi settlers from Peloria in the north of the Pass. Initially this was a trickle, but it became a flood after the Daughter’s Campaigns in Saird. By 1400, the Orlanthi settlers in Dragon Pass greatly outnumbered the Pure Horse People and the horse nomads were now confined to the southwest. The Pure Horse People forced some of the settlers (those in the southwest) to submit to their overlordship, but by 1450 even this was doubtful. The rise of the Feathered Horse Queen allowed a new community to form – the Grazelanders or Pony Breeders – where the queen ruled both the horse people and the farmers.
Sartar showed up in the Pass around 1470 and over the next score of years, transformed the tribes around the Quivin Mountains into a kingdom, with cities, roads, and markets. Hon-eel arrived in 1490 and quickly the Lunars became a faction in the north.
It is now 1625, and so the southeast of Dragon Pass has been Sartarite for about half their history in the Pass. Similarly, Furthest has been Lunar almost as long as that area was Orlanthi. Places like Bagnot or Dunstop have been Lunar for a much shorter period (a little more than two generations). Thus does that resettlement era recede into the distance.
Now remember, these people are not hermetically sealed and have traded and otherwise interacted with each other for centuries.
How did people know it was safe – was it blundering and dumb luck, heroquesting, omens, divinations? Yes. All of the above. But pretty quickly it was just that other people made it, so we can too.
What about the pony clans of the Colymar, who worshipped Elmal? Were they from the Pure Horse People? No. They called themselves the Hyalorings after that ancient solar horse-taming hero, but were Orlanthi and not Pure Horse People.
They did ride and worship horses though. Which made them stand out among the other settlers from the Holy Country.
The Grazelanders have more than a century of close relations with the Sartarites. Half their population is Orlanthi, their royal houses regularly intermarry, and they have often fought on the same side against the Lunar Empire.I don’t think a Grazelander would stand out in Runegate as being any more foreign than someone from the Far Place or Esrolia. That being said, I don’t think that the Pure Horse People and the Runegate folk view each other as kin or related in any way. Sure both have cults to Hyalor, but so do the Sun Dome Temples as well.