History of magic

Over the course of the ages, the History of magic within the realms has gone hand in hand from the creation of Toril, the ascension and abolition of gods from their planes of existence and monumental physical changes in both matter and energy.

It should be noted that some deliberate falsification of the nature of the Weave occurred in textbooks, as an attempt to limit the knowledge associated with arcane spellcasting. While the Weave was thought for eons to be magic itself, in reality it was just a means of access, though Mystryl and her successors.

Birth of Mystryl
Lord Ao created the universe. At first it was nothing but energy, with neither light nor dark, heat nor cold. Eventually the energy created two deities – Selûne and Shar. Together they created heavens and Chauntea, the embodiment of the world of Toril.

Chauntea begged for light and warmth so that she could create life on the new world, but Shar opposed this vehemently. The subsequent war between the sisters created new deities – war, murder, and destruction among them. When Selûne lit one of the nearby heavenly bodies on fire to provide the light and warmth needed, Shar became enraged, trying to extinguish light everywhere. Selûne tore the energy from her own body and flung it at Shar, where it joined with Shar's energy and passed from both of them, thus creating the goddess of magic, Mystryl. The birth of Mystryl not only brought a truce to Selûne and Shar, but created the Weave. In the newly created Toril, magic abounded in everything, but in its raw state it was too dangerous for mortals to use. The Weave was a like a fabric, consisting of many threads, all woven together to create an intricate design. Spellcasting and the use of magic items pulled individual threads and reweaved them, creating a new design. After this, both mortals and deities could use magic through this fabric that was both the embodiment of Mystryl and a conduit to raw magic.

Death of Mystryl and the Birth of Mystra
When the Phaerimm, a race dwelling under the surface of the earth, began to cast spells draining the empire of Netheril of its magic, a powerful mage named Karsus created a link to Mystryl in an attempt to steal her power, become a god and save his empire.

This caused a great rift in the Weave, and Mystryl was so weakened that she sacrificed herself to save the world. Since she was the Weave, magic immediately ceased all across Toril. A new goddess of magic named Mystra was born, and she was able to repair the weave in a way that such powerful spells could never be used against it again.

Death of Mystra and the Birth of Mystra
When Bane and Myrkul stole the Tablets of Fate from Ao, the overgod cast all the deities of the Realms out of their divine homes and forced them to walk the Material Plane in their avatar forms until the tablets were recovered. The only exception was Helm who was tasked with guarding the Celestial Stairway from any deity who attempted to return home.

Mystra, whose presence on Faerûn was damaging the Weave, attempted to get past Helm so that she could start fixing it, but Helm, sworn to guard the Stairway against any intrusion killed Mystra for her attempt.

A woman who went by the name of Midnight, who was a wizard supposedly being groomed for the position of Magister and a follower of Mystra, was adventuring to help find the Tablets of Fate. When her quest was over, Lord Ao elevated her to godhood to replace her deceased goddess.

Death of Mystra and the Spellplague
Because Mystryl and her successors were inextricably bound to the Weave, one could not exist without the other. When Mystra was assassinated by Cyric and Shar on Tarsakh 29 1385 DR, the Weave collapsed and initiated the Spellplague. As the Weave collapsed, so too did the Shadow Weave.

Permanently-enchanted items mostly survived, as they had access to magic built into them. Those with a set number of charges no longer worked, or functioned differently than when they were first created. Individuals that relied on the Weave to use magic were without the source of their power.

Over time adaptation occurred. While the Weave was no more, magic remained in existence. Some former users of the Weave "attuned" themselves to the new magic environment. Other users of the Weave came to access magic though other sources, usually deities or other such powerful beings.