That raises an interesting question - I've been thinking about what role something like siege equipment really has in a world with with a bunch of mages running around. Is it worth building and transporting a bunch of mangonel when there's a bunch of people who can achieve the same effect just by waving their arms in the air?
It's not very relevant for me, since I'm the only character disconnected from the world of incantation, but how widely disseminated is magic? When push comes to shove, what percentage of the general population can lob balls of fire or something equivalent?