The novel seem to lightly suggest a kind of mirror relationship between the Evenedricians and the Faanians:
+214: Post-Sack Convox abolishes most forms of New Matter. Promulgation of the Revised Book of Discipline. Faanian order splits away from Procian. Evenedrician order splits away from Halikaarnian.
(Anathem, NOTE TO THE READER)
The Faanians are disbanded after the Second Sack. The Evenedricians, however, continue to proliferate.
In 297, just before the Third Centennial Apert, Edhar founds his own order. An interesting sequence of events occurs (see green highlighting):
Three years later, at the Third Centennial Apert, some weird shit happened:
to go Hundred
(Derogatory slang) To lose one's mind, to become mentally unsound, to stray irredeemably from the path of theorics. The expression can be traced to the Third Centennial Apert, when the gates of several Hundreder maths opened to reveal startling outcomes, e.g.: at Saunt Rambalf's, a mass suicide that had taken place only moments earlier. At Saunt Terramore's, nothing at all—not even human remains. At Saunt Byadin's, a previously unheard-of religious sect calling themselves the Matarrhites (still in existence). At Saunt Lesper's, no humans, but a previously undiscovered species of tree-dwelling higher primates. At Saunt Phendra's, a crude nuclear reactor in a system of subterranean catacombs. These and other mishaps prompted the creation of the Inquisition and the institution of hierarchs in their modern forms, including Wardens Regulant with power to inspect and impose discipline in all maths.
—THE DICTIONARY, 4th edition, A.R. 3000
(part 4, ANATHEM, to go Hundred)
After this, the Inquisition was started. Ever after, the Sæcular Power continuously watched the concents. This forever bound together the intramuros and extramuros causal domains in an asymmetric way: the avout could not watch extramuros for threats or concerning activities, but the Sæcular Power could (and did) watch the avout.
On more momentous, thematic level, the Sæcular Power tracked the intramuros causal domains. This prevents the Apert-like events talked about towards the end of the book, where quantum randomness gets introduced, the causal domains go adrift, and the “Wheel of Fortune”-style wheel starts spinning, like Arsibalt described in this excerpt from the section meaningfully titled “Causal Domain”:
"We've become like Fraa Orolo's wandering 10,000-year math," Arsibalt proclaimed. "A causal domain cut off from the rest of the cosmos."
"Whew!"
"But there is a side effect that Orolo never warned us of," he continued, "which is that we've gone adrift. We don't exist in one state or another. Anything's possible, any history might have happened, until the gates swing open and we go into Apert."
(part 11, ADVENT, Causal Domain)
This tracking is also why Jad (and, presumably, other practitioners like him) didn’t sleep:
Stationed around the edges were baskets of extra Teglon tiles in a different color, which Fraa Jad was nudging around with his toe. It occurred to me I'd never seen him sleep. Maybe Thousanders did something else1. We left him to the Teglon.
(part 11, ADVENT, Teglon)
In one dramatic and memorable passage, Jad closes an analogous leakage while in space by destroying the radio transmitter, which was “forcing choices.”
How is any of this relevant? After the Third Centennial Apert, Edhar founds his own concent. Was he trying to reduce or mitigate this tracking by the Inquisition?
Well, if he was, what would he do? He’d found it somewhere far out of the way, not near any other major concents or civilizational centers. And in fact, that’s what he does:
"It never ceases to amaze me, what people think of us and why we're here," [Varax, of the Inquisiton,] said. "Will you please forget about this. It is nothing." He looked up at the top of the Præsidium. "Larger matters are at stake than whether a young fraa at the remote hermitage of Saunt Edhar practices his vlor on some local runagates. For God's sake," he continued (which sounded funny to me since few of us believed in God, and he didn't seem like one of them; but maybe it was just an oath used by cosmopolitan people in the sorts of places where our concent was thought of as a "remote hermitage").
(part 2, APERT, Bulshytt)
We can’t know whether this was deliberate and smart or accidental but providential. The sequence of events suggests deliberate and smart, but evidence in the other direction is that the theories for even thinking about any of this in a sophisticated fashion weren’t developed for another thousand years. And obviously none of the radiation damage theory/praxis would have existed yet.
This is an example of something the book does in several places, including a couple in this chapter, which is basically assume that the Thousanders atop the Crag were all Third Sack praxis practioners. Since this is always the frame. and never the implication that Jad is somehow one-of-a-kind or the last living practitioner, a relic, I take this as weakly word of God.