Elminster in Myth Drannor: Forgotten Realms: Elminster, Book 2

It is the time of the great elven city of Cormanthor, when the Heartlands are home to barbarians, wicked dragons rule the skies, and the elven people trust no one. Wizards and warriors alike threaten their civilization in vain, arrogant, and ignorant quests for glory.

Thus it was that Elminster was guided to Cormanthor, the Towers of Song, where Eltargrim was Coronal. There he dwelt for 12 summers and more, studying with many mighty mages, learning to feel magic and know how it could be bent and directed to his will.... It is recorded that when the Mythal was laid, and Cormanthor became Myth Drannor, Elminster was among those who devised and spun that mighty magic.