Mages are those characters gifted with True Magic. There are four ranks of mages, the higher a level of complexity and the more power a spell requires, the higher a mage must be ranked in order to cast it. The four ranks are:
An apprentice mage studies at a school or under the supervision of an individual Master- or Adept-class mage. After this round of study is complete and the apprentice has demonstrated mastery, they become a Journeyman. Not every mage is born with a strong enough Mage-Gift to advance farther. In fact, hedge-witches and wizards don't have a strong enough Gift to reach Journeyman and be considered true mages by most other magic practitioners.
While some schools, such as the White Winds School, teach that only Adept-class mages can draw power from outside themselves for a spell, the Tayledras teach that Master-class mages can do so as well. External power exists in two forms, in ley-lines and in nodes. Only Adepts can access and utilize node energy without burning themselves out. However, Master-class mages can access the less powerful ley-lines, with proper instruction. This ability to draw on all external sources to power their spells is much of what makes Adept-class mages so dangerous.
The mages of the Eastern Empire parse out the four basic rankings into a sophisticated hierarchy. The Master class is divided into First and Second Rank, and them further subdivided by color, starting with Blue, Purple and Red. Tremane was classed as a 'First-Rank Red' Master mage.