The Sorcerers' League's base in Dalaran as seen in Warcraft III.
This article contains lore taken from Warcraft III: Reign of Chaos, Warcraft III: The Frozen Throne, the manuals, and/or official bonus maps.
The Sorcerers' League was one of three factions within Dalaran, including the Kirin Tor and Mages' Guild, which tried to hold back the forces of the Scourge during Arthas' siege of the city during the Third War.[1] These three factions were also the ones trying to prevent Kel'Thuzad from summoning Archimonde outside Dalaran (or simply trying to destroy the Scourge, unaware of the summoning).[2]
In Reforged's Under the Burning Sky, the Sorcerers' League was replaced by Alliance Defenders, indicating that Dalaran didn't fight alone against the invasion.