The Chantry

The Chantry is composed of scholars, religious clergy, and politicians who oppose further liberalization of magical use, and instead push for restrictions upon it. The official line of the Chantry is elimination of all magic that does not come from a divine source or guidance, but not all members carry such an extreme perspecitve.
The Chantry does not have any formal structure, but they do have so-called "cloisters," where people may attain education on their perspective and, more commonly, be sent for a religious education. Different cloisters favor different deities from among the Ones Above, but most see a wide range of applicants, primarily from peasants seeking for their children to escape from poverty. Cloisters have developed a reputation for poor conditions and abuses, including things as serious as hard manual labor, and are referred to by detractors of the Chantry as "voluntary serfdom," a dig on the fact that they often advertise themselves as alternatives to peasantry.
Witch-Marked children (especially those orphaned) often fall into the hands of the Chantry. While this fate is unenviable and often guarantees isolation and experimentation, it's still (arguably) preferable over the fate that a rural mob might bestow. Those who survive their childhood in the Chantry are typically not permitted to leave even well into adulthood, but many escape and centers of magical learning are eager to provide them with sanctuary and rescue.