Now, this is confusing, because none of the other Emperor's Sons made any recorded attempt at overthrowing Jagar Tharn (who they would of thought was just their father out of his mind), and they could of gotten a larger supportbase from the population than Calaxes (because, I highly doubt that even in Cyrodiil, a proposed Theocratic rule would of gone down well with public opinion), however this could be due to the posible double-gangers put in place by Jagar Tharn (or atleast the rumors from morrowind seemed to indicate).
So, what I'm wondering is if Jagar Tharn, fearing revolution and the provinces breaking off, tryed the tactic of "making-up" a fake Bastard-Heir, gave him some power in the church, and then got his advisors to put into his head ideas of Theocratical Revolution, and from there all Jagar Tharn would have to do is to kill this made-up identity of Calaxes Septim, when the rumors of his uprising spread just enough to scare the people; from which could 1) put fear in the supporters of Calaxes 2) put hope and enthusiasm into the people of Cyrodiil, to reassure them that he was a good leader.
So, how well does this Theory go down?