Okay so I am kind of taking all of you on your words about past in-game lore references, so forgive me if I do not make any sense.
Sounsyy said that White Magic was something forgotten or abandoned in the 5th Astral Era, right? And we have established that the Padjal came later when the Hyurs joined Gelmorra, long after white magic was discarded, right? I haven't actually done the White Mage Job quest yet -- that is, I didn't do it in 1.0 -- so maybe I am missing something there -- but that would lead me to believe that the Padjal cannot be the only keepers of white magic secrets, this meaning that I find myself in agreement with what you were just proposing, Catapult. That is, if White Magic preceded Padjali. That being said, maybe white magic did lend the foundation for conjury, perhaps from the Padjali discovering it somehow, maybe by way of commune with the elementals, which would also mean that conjury happened during the reconciliation with the elementals as opposed to as a result of such, non? Do we know who the original white mages were in the 5th astral era or what white magic was primarily used for then or why it was abandoned/forgotton at all (my grammar is awful here)? The elementals, fearing the return of the intense white magic, might have conveyed only a small part of it in this new conception of conjury, tempered by a need to keep balance through use of selective elementally aggressive magic, and an insistence to follow their will (to avoid another white magic disaster? Again, presuming there was a dramatic reason why it was abandoned/forgotten in the 5th Astral Era).
And why does my bloody internet browser think that "elementals" and "conjury" do not exist as words? Curse ye, Chrome. Curse ye.
(Oh, and please help me sort out how to properly pluralize Padjal and where to do so and which suffix means what in where. Padjali is the plural? Maybe? Or is it like "belonging to Padjal" there?)