Evoker, Mages Guild achievement in The Elder Scrolls IV: Oblivion

Just for reader's reference, "A Mage's Staff" is the first quest you receive after completing all of the Mage's Guild recommendation tasks, and officially become an Apprentice. The "Ulterior Motives" quest is received from Raminus Polus after completing "A Mage's Staff", and upon completion the player will be promoted to the rank of Evoker (with achievement to match).