Gaius has told us when, I just can't remember what he said. It was during that quest where you pilfer the wreckage of a ship he conveniently crashed for you.
I'll have to look up my recording (after live letter is done).
Also, do we know the dragons of Dravania worship Bahamut for sure? Logic suggests their affiliation was closer to Midgardsomr. That being said, Ishgard now has more of a reason to get involved now, dragon-haters that they are.
EDIT:
Here we go. From the quest "Don't hate the messenger."
Well, that gave more insight to the what but not the when. Let's jump to United we stand:Gaius:
I will not deny that the primals have proven a great nuisance. They have delayed our advance. It was to break the stalemate between us that Nael van Darnus sought to bring down Dalamud.
The impact of the red moon would destroy the primals in an instant. Little wonder that His Radiance embraced the scheme.
But Dalamud is no mere rock, despite what van Darnus would have us believe.
It is a great red sin, exiled to the skies by ancient Allag. There has it long festered, becoming something far more vile than we ever supposed.
I see proof of this in van Darnus. His manner is...altered. He is anxious. Uneasy. He deceives His Radiance.
Of those in your realm, only the son of Midas nan Garlond sees the red moon for what it is. His Radiance will reach the same conclusion in time.
Yet by then it will be too late. The shadow of Dalamud will already be dark upon these lands.
Oppose van Darnus and Meteor, if you wish. It is the only hope you have of sparing Eorzea from complete obliteration.
and now on to Kill a Raven:Nael:
But no more, for I shall halt the turning of this wheel of darkness! He has willed that it be so, and so it must be!
A few interesting finds, but alas, no era of note. Although I could have sworn something told me it was the third era... Gah!Nael:
It was I who raised for Thee this stout sanctuary, using the wisdom of ancient Allag and the offering of mine own frail flesh!