Some articles on highmage:

Wizards Of High Sorcery - Conclave
... The Highmage is chosen among the Conclave (most of the times among the Heads of the three orders) to lead the Conclave of Mages ... of High Sorcery on Ansalon through the consensus spell - the selected Highmage is then surrounded by a corona of light according to the feelings of the majority of Ansalon's Robed Mages ... Conclave wizards (even the Highmage) remain in their position until either their death or their removal by the rest of the Conclave ...