... do we know when the white council was actually created? I can't remember any hard evidence other than when Edinburgh was won...
https://www.youtube.com/watch?v=ODOhEdiFwW0&t=1733s"The origins of the WC were pretty nebulous... they were an advisory board to the Roman Senate for a long time"
But then Merlin reorganized them after the fall of Rome, for fear the powerful wizards (now ambitious independents) would war among themselves.
"for a long time" isn't terribly precise. We don't know if they coalesced after Rome demonstrated its hegemony in the region, or were an older group that attached itself to Rome, or were part of the founding (which would firmly place them around 750BC(ish))... q.v. "nebulous."
Similarly, "fall of Rome" is pretty indeterminate... a long slide from about 375AD to 475AD; so there's at least a century where Merlin
might have reorganized the old Roman group into the new White Council (and whether that took just a year or two, or decades, or even a century... also unclear).
No idea if this is something Jim just hasn't decided, or if he's intentionally obscuring something (for a later Big Reveal), or what.