I want to know who founded the battlespire and when. I know it is pocket dimesion of oblivion but was wondering wether it was just found by the empire and taken over or was it built by the empire.

There are some hints in the game that Clarentavious Valisious was one the battle spires architects, or at least of the anchors that keep it in place. Although I don't know how old he is, it does make it clear that the Battlespire is man made and was made in a not so distant past.

Unless Clarentavious Valisious is Dyviath Fyr, then it might be as old as the Empire.

Sorta like the ISS really.

They talk about it in Redguard, so it must have been around before the start of the third era at least. It has to be second empire sometime after the founding of the Mage's Guild in 2E 230 and 2E 431 when the civil wars erupt.

In that case, I'd go back all the way to the first Empire when the Battlemages were created.

Heck, maybe the Nibeneans jacked an Ayleid portal and created it to get away from those insufferably boring Alessians.

But why do you think the Imperial might be Fyr?

Both are grumpy age old Dunmer with a fairly extensive knowledge of Oblivion, but mostly because of Fyrs collection of Battlespire artifacts.

I was considering the Mages Guild as the major source of funding to get the project going, I don't think it would have happened before then unless the BM's found a powerful sugardaddy.

There is no such faction as "The Battle Mages", they're a class that came into existence to fight the Elves and later on turned into an aristocracy. Not much of a surprise considering the considerable amount of learning required probebly rubs off in the other aspects of live as well.

The Battlespire is an military academy, think Sandhurst or West Point and as such it is most likely funded by the Legion.

Hmm - if I was Ocato I would be looking to build some kind of replacement for the Battlespire very quickly.

As a speculation it looks like one of the major achievement of Dagon's assault on the Spire was that there is no more Training Ground for Battle Mages ... hence a lot more work for PCs. You have to wonder how much more difficult Dagon's latest little plot would have been for him if a couple of battalions of Battle Mages had been on call?

It was abandoned and the training grounds were relocated to somewhere on Tamriel IIRC.