Military action
“I am going to go into this world, and I don't care if you and your narrow mind cannot be a part of it.” ― Elise Kovan, wild sorceror
In the 4th era, the re-discovery of a permanent portal to the Feywild by humans led to a chain of events in which almost all mortal mages became embroiled in a war against each other. After much destruction and the spread of many magical fallout zones (wild magic, dead magic, shadowblight zones, etc), the war was ended when Lord Orion of the Summer Court, an Archfey, declared a forcible armistice between the three largest factions by binding shut the mouths of every person who knew battle magic for a year, during which time a peace was negotiated by anger letter.