Flaems, Cypri and True Alphatians
by Ville LähdeI did some work on this a year ago and ended up with something like this:
The original Cypri were a distinct people that were conquered by the growing Alphatian empire.
At that time it seems that the Alphatian empire was mostly populated by "True Alphatians", although we might speculate that they had already conquered various peoples who had been integrated to the empire. So the True Alphatians would have been an inbred elite ruling class, a bit like the royal Melniboneans in Moorcock stories. (But this is just speculation.)
Anyhow, after the submission of the Cypri people they were slowly integrated into the Alphatian population, bringing their features to the "Common Alphatian" stock. Also the elite status of the "True Alphatians" seems to have diminished.
During the subsequent generations it seems that the puristic True Alphatian sect remained, and the leaders of the Followers of Air rose from their ranks. But it is likely that there were followers from many other groups as well.
The Followers of Fire most likely were just as diverse, but perhaps their leading cadres had some families that had remained more Cypri-like, perhaps due to similar puristic attitudes as with the True Alphatians.
When Old Alphatia was devastated by the elemental strife, the Followers of Fire abandoned their enemies to the wasteland and left - ending up in Mystara. In Mystaran Alphatia we again meet the concept "True Alphatian". It is likely that the leaders of the Air faction also led the migration, and thus regained some of their elite status.
Some of the Followers of Fire - who had abandoned Alphaks's teachings - left Old Alphatia later, and they embarked on a long exodus via the Plane of Fire. Again it seems likely that the puristic Cyprite families led this exodus, which might explain the strong Cypri traits of the Flaem who arrived in present-day Glantri.
I'm not sure if genasi blood (or some other equivalent, depending on the game system) would be likely in the case of the True Alphatians. But in the case of the Flaem it is more than likely.