Disclaimer: Wizards of the Coast do say that they don’t have an official timeline and some of their lore is no longer considered canon. There are many reasons for this, but mainly it’s so that you can pick up any of their modules and not have it feel out of date. That said, this is my understanding of what’s out there, and in some kind of timeline order.
Dungeons and Dragons has a rich world and with that comes an extensive amount of lore; lore that can be difficult to put together and make sense of. So, I’ve done all the hard work, meaning that you don’t have to. We will start off where everything began – and the very thing that makes looking up lore for Dungeons and Dragons so complicated – the creation myth.
A story has been passed around the people of Faerûn by the Clerics of Chauntea, Selûne, and Shar, of how this world was created. It goes as follows:
The universe was created by the OverGod, Lord Ao. Within this universe was the planet Abeir-Toril – later to become the twin planets Abeir and Toril, when they were separated during the First Sundering. Faerûn and the stories of the Forgotten Realms take place on Toril.
For a period of time this planet was a timeless nothingness, a misty realm of darkness, even before the concepts of light and darkness were separate ideas. Out of this the deities of Light (Selûne) and Darkness (Shar) were created. Together, they created the heavenly bodies, and the deity Chauntea. Selûne provided light, while Shar beckoned in the darkness.
Chauntea – now newly created – wanted warmth to nurture life and living creatures upon her form, this caused the twin deities to become divided in intent. The two fought and from the conflict, created other deities such as: war, disease, murder, death and many more.
Selûne reached into the Plane of Fire, and by using the Pure Flame she pulled from it, she ignited the largest of the heavenly bodies creating a sun and giving warmth to Chauntea. This action angered her twin, Shar, who began to snuff out light and warmth within the universe. Weakened and desperate, Selûne tore the divine essence of magic from herself and threw it at her sister, tearing through her, and pulling away the same magical essence from her, creating a new deity, Mystryl, the deity of Magic. Mystryl was composed of both light and dark magic, but she favoured her first mother, Selûne. Now outmatched, Shar retreated into the void.
The birth of Mystryl not only balance the war between the twin sisters, but changed the reality of the universe altogether by creating the Weave. The Weave was the conduit that allowed creatures to use magic, not just something that was restricted to deities. Any creature with the talent or training could learn to call upon the power of the Weave.
Entities known as the Primordials already inhabited these planets, although they were originally from the Elemental Planes (such as the Elemental Plane of Fire). The Primordials found some sections of the Prime Material Plane (the Plane that Dungeons and Dragons is usually set on), to be either ‘too bright’ or ‘too dark’. They tore away these sections of the world to create the Feywild and the Plane of Shadow, which would later be come to known as the Shadowfell.
The Primordials wanted to take over the planet of Abeir-Toril, to become the true rules. When the deities, Selûne, Shar, Chauntea and Mystryl discovered this, the Gods and the Primordials went to war. This event became known as The Dawn War.
 pronounced, fay-ROON
 pronounced, chawn-TEE-ah
 pronounced, seh-LOON-ay
 pronounced, Ay-Oh
 pronounced, ah-BEER-tor-RILL
 Chauntea has also been seen as the Avatar of Abeir-Toril, an embodiment of the planet itself. This is why it states that she wanted to nurture life upon her form. It’s a poetic way of saying bring live to the planet of Abeir-Toril. This has caused some confusion due to her being both a deity to worship and a planet?
 pronounced, MISS-trilh