Ahghairon (pronounced: /ɑːˈgɛərɔːn/ ah-GAIR-awn), born Ahghairon Belnoth Undrur, was a mage from the North and the first Open Lord of Waterdeep.

He created the Lords of Waterdeep, the system by which Waterdeep had been ruled ever since, except for a six-year period immediately following his death.

https://forgottenrealms.fandom.com/wiki/Ahghairon