I'm sure this has already been brought up somewhere, but I was looking through the lore of TES on UESP (The Unofficial Elder Scrolls Pages) and found an interesting tidbit that I think has a great deal to do with Skyrim:
Skyrim was absorbed comparatively peacefully in the empire of Tiber Septim, the Battle of Sancre Tor and other clashes notwithstanding. Many Nords found employment in the Imperial Legion, as Talos generally nurtured relations with the north. In the centuries after the Empire's founding Skyrim was drawn in several major conflicts. One of these was the War of the Red Diamond wherein Skyrim sided with Queen Potema against the Empire. The civil war tore the Empire apart and it would take seventeen long years before Potema was finally defeated. As a result of this war there is a strong underground movement called the Horme that believes Potema and her deposed son of Uriel III to be the last of Tiber Septim's true blood and under that principle lead raids against Imperial interests in the province.
This information is taken from UESPWiki.
What does everybody think? Is this the heir of the Potema/Septim bloodline? Are we going to be assisted by both the Greybeards and the Horme faction? I think this is a perfect fit.