Things we know:

*The Magus is an earned title, always earned by an Apprentice.  There was a different Magus a hundred years ago, and that position has passed through at least two hands by now.
*It is apparently tradition in the world that if the Magus calls you, you must answer.
*Ravenhall is on Ravenhall Island, in the middle of a river
*Gnomes are a thing, at least in Ravenhall's Rose Gardens (and possibly Menagerie?)