...And then Dawnguard came and flipped that on it's head. Apparently Jiub didn't die in Morrowind. Because he wasn't even in Morrowind to begin with. He was in Kvatch. That city was destroyed before the Oblivion crisis even started.
This premise is so full of contradictions it doesn't make sense. While one can say "It's a rumor, it isn't immediately fact" - apparently rumors in Oblivion were so accurate when it came to events that they were considered canon. (Such as Vehk's disapperance, Ald'Ruhn destroyed, and so on)
But yes. Saint Jiub was in Kvatch writting his 26 Volume Epic (He's a John Milton, that Jiub <3)...But then this brings something into the field. If apparently nobody was talking about this apparent Living Saint now coming to Cyrodil and intended on living in Kvatch and apparently nobody decided to tell anyone in Cyrodil that he left Morrowind..then why say Saint Jiub died in Morrowind fighting the Daedra during the Oblivion Crisis?