All magic hails from the age of the old kingdom. Invented and embedded into the land for its people. In essance the magic is alive.

Sorcerers are the people who inherited this magic. Its part of their blood.

Druids are not Old kingdom based but have learned to harness the magic from nature.

Clerics and paladins of all kinds are the same. The magic doesn't differentiate by god. Only alignment. But the religious don't know this.

Psionicists work in a different way. They have attuned their bodies to emulate that of the Old kingdom peoples. They have tricked the magic into working for them. This trickery can be felt. But is generally considered harmless and partly natural.

Wizardry is fairly new to Albion. It was invented soon after outlying islands began immigrating into Albion. It FORCEABLY pulls and bends the magic. The effect is so unsettling to other magic users that it can be felt even if not seen. This magic is considered an abomination. And some suspect that it will lead to the destruction of Albion. 

There are rumors of other ways to harness the magic of the Old kingdom but nothing substantial has come of these rumors.