I like the interpretation from the old Covenant Book. The "Circle" is a generic term to refer a bunch of loose cults scattered across the globe, each one with their own History and often barely or even utterly incompatible between them. Only the pressure of the Santified (and their equivalents from other societies) forced them to set a sort of unified front.

And it's very explicit about how the way a cult exercise their faith can differ from how they used to centuries ago. Some of them are modern reconstructions based on ancient texts, and others are lead by ancient with...