Scio Occultus Res
A mage’s mentor is the mage who taught the newly-Awakened Sleeper the fundamentals of magic. In mage society, being a mentor is a respected and valued calling: it prevents new mages from being snapped up by the Seers of the Throne or becoming deluded Banishers, it grants new mages protection from these dangerous groups and others, it gives the new mage a chance to make an informed choice of Order, it allows new mages to learn proper etiquette and tradition, and it fosters generational ties within the society.
A mentor usually only keeps a new mage who joins his own Order; a mage who wishes to join a different Order is passed to a different mentor, though many mentors will do their best to persuade the mage to stay and strengthen their Order.
Once a mentor declares a mage well-trained enough to stand on his own, he is introduced to the Consilium. At that point, the new mage is considered to be responsible for his own actions, and fair game in the political games of Awakened society.
The bond between mentor and pupil may or may not survive this parting, depending on what the relationship between the two was during the teaching period.