Board Thread:Lore Discussion/@comment-8248675-20130606043855/@comment-9887604-20130606143525

There's no definitive answer one way or another. He could have been either Atmoran or Breton from either of the major accounts. He adopoted the name Tiber Septim to better help his transition into Imperial politics. Talos literally means storm crowned. Personally I think a mixture of both stories is closer to the truth. However the fact that he was a dragon born would make me think he was Atmoran for the simple fact that there are not any other recorded races of dragonborn.