Trust me, I was just as surprised as you are when the thought popped into my head the other day.
But if the Architect is a Tevinter Magister of old as well (as it's pretty obviously implied to be the case) I'm talking about in the REALLY OLD DAYS of Tevinter. Like, from Corypheus' era.
Don't know why it happened, don't know how it happened. But... it happened. And now it's something I'm sticking with.
I'm surprisingly not alone in that ship though, it seems. Seen a few posts on tumblr showing such things after the thought sprang up.
See here for one such post:

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