Can you identify this book? Here's what I remember of it...
A civilization had their home world ravaged by some kind of disaster. Using "Greater" magic they made a portal to another world.
The story is about this civilization a long time after this disaster and there are two types of magic, "Lesser" and "Greater". Lesser magic is parlor tricks and small scale magic, whilst greater magic is capable of controlling the elements.
The main protagonist pursued a lesser mage and convinced the mage to teach him.
Sometime after he learned lesser magic, mages that study greater magic kidnap him after learning that he has the potential to learn greater magic (Greater magic is more rare than lesser). The boy is taught how to use greater magic in a tower where he is unable to speak and is put through a harsh training that almost erases all aspects of what he learned as a lesser mage.
One thing that i remember about greater magic is their capacity to "teleport"; every location that a mage wishes to go to must have a mural on the ground that the mage must go and memorize in order to return there.
I also remember something about an arena where the main protagonist (after learning both lesser and greater magic) goes to. In the arena is an old friend of his (?), and that person is fighting to the death against others. The main protagonist gets mad and uses his abilities as a mage to wreck the arena and to threaten/terrify the nobility that were amusing themselves using the arena.
At the end the main protagonist ends up making a giant school and proceeds to teach both lesser and greater magic in order to train students and make magic less "taboo" and rare.
Please tell me if anyone knows a story/series that fits this description and if you need more details I may be able to help. It has been a while since I read this book though so some details might be messed up.