The elven Magus Guild is run by the Archmagus and is located in the capitol city of Lyl, in the nation of Syll. The Guild takes on young would-be mages that have fulfilled the basics of spellcasting and memorization with a minimum of 50 years of age. Elves start learning magic in their adolescence, around 30 years and can spend up to the next 20 years researching the appropriate spells to inscribe into their books. If the elf isn't accepted into the guild, they can enter the military as a mage combatant, having a little magic, but not full mage status.
Once they have mastered all of the spells in their apprentice books (usually up to 6 which takes another 20 - 25 years) they are granted Nan Magus
status. If they work hard and show the promise due to a master mage, then by the age of 100 they are then considered Journeyman Magus
and are allowed to leave the city and practice their craft unsupervised. As the Journeyman Magus gains more spells and learns to wield them, they can apply back at the guild for full Magus status, giving them even more prestige among the casters of the world. After that, over the course of decades of research, they can move on to Master magus, then Archmagus.
Benefits of belonging to the Magus Guild include free admission to the great Library of Lyl, price reduction on materials from the guild itself, and recommendations for any employment they may need in the course of their membership. Cost of the guild is sharing of the knowledge they have acquired over the course of their studies.