>>I think both myths refer to the same mythical/prehistoric event. Then they
>>diverged and were finally merged again by the Council
>
>This could well be, though it's odd that such major details as who were the
>Emperor or Rebellus Terminus were forgotten.
The actors in a story are seldom more important than the act, and when the story spreads the actors will be replaced by others that are a better fit culturally. The same happens when the spreads through time - the actors who were appropriate before aren't any longer and so are replaced by new talents. There are quite a lot of examples to back this claim up, but they are all in the RW, so it might not be directly applicable to Glorantha.
Of course it happens the other way too. Just look at the myths about Heracles - the actor has stayed the same but the act changed drastically when the stories spread to new climes or new times. New myths were also grafted onto the same mythical figure.
Thus, i don't think it's odd that names of the Emperor and the Rebel were changed. The roles and the script stayed roughly the same but fitted with new actors.
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