Allagans in Tural?

[Cleretic]

I think you might be misremembering. Allag started with Xande as an empire and the first thing he did was to collect mages for his army to conquer Eorzea.

"Xande used his uncanny intelligence and charisma to build a nation that, while founded in science, did not deny the magic of the Second Astral Era."
"In less than a year, Allag was the largest nation in Eorzea and Xande crowned himself emperor."

This is a bit of an interesting passage, becuase if we take it literally then it's... sort of impossible? Like, you can't just come out the gate and found an empire day one; typically, a nation of another type becomes an empire, usually by conquering other nations. For some in-game-rooted examples, the Roman Empire has an origin pretty close to Garlemald, where a republic became an empire under one guy deciding to do things differently. The Mongol Empire started when the guy we know as Genghis Khan was elected leader of a bunch of different tribes, which you could potentially read as similar to Gulool Ja Ja (but I would argue probably isn't an especially accurate reading of either figure).

Put simply: there's no way that we aren't missing details here, because the founding of empires just don't work the way that the EE1 describes Allag's origins. What those details are, I couldn't tell you. My honest best guess is that Allag maybe started similar to the Mongols, as a pile of disparate tribes unified under one banner, but that's based on a reading of one sentence in the EE1.