The Colleges of Magic are the eight great institutions of human wizardry, founded in Altdorf in the aftermath of the Great War Against Chaos. Before them, the Empire burned its wizards as witches — with some justice, since untrained humans meddling with the Winds of Magic rarely come to good ends. But Magnus the Pious had seen what sorcery could do on the battlefields of Kislev, and he petitioned the high elves for aid. The archmage Teclis of Ulthuan remained in the Empire to establish the colleges himself.
Teclis's founding insight was specialisation. Human wizards cannot safely weave multiple winds, so each college binds itself to a single one and its lore: the Bright College masters Aqshy's fire, the Amethyst College the death-magic of Shyish, the Celestial College reads fate in Azyr, and the Gold, Jade, Grey, Light, and Amber orders each claim their own. Every college keeps a headquarters in Altdorf, most of them magically hidden or strange — the Bright College a perpetually burning citadel, the Grey College glimpsed only through fog.
In exchange for legality, the colleges lend battle wizards to the Empire's armies. It remains an uneasy bargain: witch hunters watch the orders narrowly, common folk mistrust anyone in robes, and every graduate knows a single catastrophic miscast could prove the mob right.