[Excerpt from a book on the esoteric practices of the Abbey]
Once a child shows the proper inclination, he is marked. Overseers are assigned to study the subject, surreptitiously, in order to determine whether this inclination is supported by cosmological conditions and other signs, ongoing throughout the year.
At the end of the cycle, those befitting further testing are removed from their homes some hours before dawn, and must begin the march to an outpost outside the city.
There, the children undergo ritual preparation and evaluation until the last night of the Month of Rain, when they make a pilgrimage to Whitecliff. During an elaborate ceremony, it is determined which of the children will become Overseers and which must be put down.