Board Thread:Lore Discussion/@comment-8248675-20130606043855/@comment-3539474-20130915005404

Dovahsebrom wrote: "When the Nord armies of the First Empire finally entered High Rock and Cyrodiil, they found Bretons and proto-Cyrodiils already living there among the Elves. Indeed, the Nords found it difficult to distinguish between Elf and Breton, the two races had already intermingled to such a degree"

-Frontier, Conquest

This quote basically says that Nords never met Mer-Men breeds until they ventured out the borders of Skyrim, proving the Reach has indeed always been a part of Skyrim and never High Rock. Yes, the Reach are part of Skyrim. But Nords are not native Reachmen. Reach had little population at the time, with the proto-Bretons and Snow Elves hybrids.