There is but a single absolute requirement for holding a high seat on the Grand Council of Absalom—one must simply possess one of twelve magical cornucopias and present it at a secret gathering (known as the Starstone Exaltation) held once a year. These horns are said to have been crafted at the time of the city's founding, some say by Aroden's own hand and from the Starstone itself, though little is actually known of the horns' origins. Obtaining one is often far from simple, as any discussion of their appearance, function or location is banned by law.
It is an open secret that each magic horn has its own name, though such details are truly secret. Though its authenticity is highly suspect, there exists a single epic poem that describes the nature of one of the 12 horns, which the saga names Nightbane. The poem is well known in Absalom, and thus no action is taken against those repeating it for fear of suggesting the verses are true. Although, it is possible that the Grand Council may simply be ignoring it merely because the tale is entirely fictional.
The cornucopias are closely guarded by their possessors, as any individual who presents one at the annual Starstone Exaltation meetings is guaranteed a position on the Grand Council. Should one ever change hands the high seat would change as well, even if the horn were to be obtained through illicit or dishonest means. Even so, the actual location of the meeting is secret in itself, and transfer of the title of high seat does not occur until the meeting actually begins. The holder of a cornucopia recognizes the other 11 on sight, thus insuring that forgery of one of the relics is not an option, even though each is unique in appearance.
In addition to securing seats on the High Council, the cornucopias are also capable of the creation of enough food, water and necessary supplies to withstand any siege. While the official reason for the failure of every attempted siege on the City at the Center of the World has always been the sheer number of clerics within the metropolis who can magically create, transport or summon food and water for the people of Absalom, the cornucopias have always played a major, if secret, role in the city's survival in times of need. This magical property only functions when maritime and overland supply routes into Absalom are blocked by invading forces, the horns ceasing to provide for the city once a siege has been broken.