WORK IN PROGRESS
Mystra was the goddess of Magic on Faerûn. Almost all mages got their power from her Weave.
Agôn Mhïyr and the Cataclysm Edit
After defeating Agôn Mhïyr, Mystra was left substantially weakened. It was then that Kareska, the rivaling god of magic, sought the finishing blow and ended her. The weave shattered and the cascading consequences were felt throughout the Realms, causing the True Cataclysm.