I was wondering, would it be possible to resurrect the Septim emperors? They are all Dovahkiin, and as such their souls should persist, rather than traveling to Aetherius.

It should be possible for another dragon, or dragonborn, to resurrect them using the thu'um "Slen Tiid Vo". If one of the Septims were to be resurrected, they would have legitimate claim to the Ruby Throne.

What are your thoughts on this? Would it be possible? If so, would it be a good idea?

Martin absorbed the souls of the Dragonborn emperors when he shattered the Amulet of Kings and turned into the statue that's sitting in the Temple of the One. Seems like they're not effectively inert at this point.

Did he? I've not actually finished Oblivion's main questline yet, so all I know about that is what I've read in Skyrim. The books I've read in-game make no mention of him absorbing souls, nor does the wiki. I'll have to look into that.

The necromancers in Wolfskull cave seemed pretty convinced that they could resurrect Potema Septim.

"The wiki"? Are you referring to the Elder Scrolls Wiki?

Because that's the last place you want to use if it comes to lore.

By "The wiki", I actually meant the UESP. I guess I should have said that, but for some reason I always think of that as the Elder Scrolls Wiki. I actually forgot that the other one exists.

As for the Necromancers at Wolfskull cave, I actually hadn't thought about that. However, Potema's ghost or spirit or whatever that was there looked very different to most Dragon souls; clearly there were using a different type of magic to resurrect her. Still, I guess that doesn't matter. Their spell was successful either way. (or it would have been if it wasn't interrupted).

She would be the rightful heir (though whether their name will still hold water with the Mede's or...whatever the hell's happening down in Cyrodiil.) by all accounts, but whether or not she'd have the divine backing the Mede's didn't have is another question. Seeing as she was defeated twice, but assumption is no.

Even if she didn't have the full divine backing that the Septims had when they were alive, it still seems like she would have more than Mede. After all, she was a dragonborn empress, and I can't think of any reason why she wouldn't still have that title.

She never took the throne, so her being Dragonborn is suspect. But goes back into the whole off-topic of how or what Septims actually made the cut if they all didn't already posses the title, which is a whole other kettle of fish.

You're right, I forgot that she was never actually empress of Tamriel. On a bit of a different topic, I wonder how widely accepted Potema's claim to the throne would be if the LDB didn't kill the necromancers.