Could someone reiterate that particular theory for me?
I can't imagine such a thing. My interpretation was that the Solas of the old world had been in a position of authority before he went renegade.
So was Abelas, apparently, yet he wore Mythal's vallaslin.
Anyway, people assume that Solas wore a vallaslin, and it was most likely Mythal's, predominantly due to Cole's suggestive comment in Trespasser: "He did not want a body, but she asked him to come. He left a scar when he burned her off his face."
Since a great deal of Cole's cryptic comments in Winter Palace is about Solas and his past, it's hard to assume that it'd be about anyone else - or that it is about anything other than vallaslin. That Solas has a noticeable scar on his forehead (AND that he knows how to remove vallaslin) only makes the impression stronger.
And yes - Solas was likely in position of authority. But that position of authority appears to be guarding Mythal, according to codices we find in Deep Roads section of Trespasser:
http://dragonage.wik...oads,_Section_1
http://dragonage.wik...oads,_Section_2
http://dragonage.wik...oads,_Section_3
from section 1: "These statues are old. Better shape than anything I've seen on the surface. Many of them are for Mythal, though. And Fen'Harel. Not in a spot of honor, but guarding, attending."
edit:
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