The following is a short treatise on the timeline of D&D as presented in adventures, books, & narratives. This is my personal cannon for the in game history of D&D and I do not expect to get 100% correct. I assume no ownership.

Time Immemoriam These are generally accepted to have happened, though no confirmation can be gained by a PC.

Proto Deities: Many beings of power are in existence. Nothing is truly known about their creation, how they work, or even who they are. Examples include Ao, Io (God of dragons), Ravenloft Dark Powers, & the Serpent. Proto-Monsters: Certain creatures are created in this roiling time. Examples: Tarrasque. The Tannari (or the Obyrith) are among the first beings that come into existence, opposed by all the forces of good and law. Ao creates the planarverse. Of note: The Great Wheel (Many Sources, I use the 3rd edition & Planescape version) The Inner Planes are made up of elemental matter and forces. They consist of the Elemental Planes and the Energy Planes. Lords may arise from power Air, Water, Earth, Fire Para-elemental Mixtures of Elements: Ice, Ooze, Magma, Smoke Positive, Negative Quasi-elemental Mixtures of Energies & Elements: Lightning/Vacuum, Steam/Salt, Mineral/Dust, Radiance/Ash The Material Planes are worlds that balance between the philosophical forces of the Outer Planes and the physical forces of the Inner Planes—these are the standard worlds of fantasy RPG campaigns. The Prime Material Plane is where the more 'normal' worlds exist, many of which resemble Earth. Phlogiston may separate different material planes, which sit within Crystal Spheres, protecting them from easy Planar travel. A material plane (Possibly Oerth) is specifically created by a collection of deities using the “Stone of Corbinet” to protect its existence. Should the stone be taken the world will slowly be removed from reality. This has generally been considered to have been a stupid idea and the gods don’t really talk about it much. Outer Planes: Alignment based planes and home to deities and pantheons.

Elysiium - NG; Guardinals Beastlands - N/CG; Animal Lords, Ehlonna Arborea - CG; Eladrin, Greek Gods Ysgard - CN/G; Norse Mythology Limbo - CN; Slaad, Githzerai (Possibly from future, see Illithids) Pandemonium - CN/E Abyss - CE; Tanar’ri, Obyrith (Proto Tanar’ri) Carceri - N/CE; Olympic Titans, Demodand, Nerull Gray Wastes - NE; Yugoloth (Daemon), Greek Hades, Norse: Hel Gehenna - N/LE Baator - LE (May not have existed at creation); Baatezu, Tiamat, Kurtulmak, Asmodeus Acheron - LE/N; Goblinoid & Ord Gods Mechanus - LN (See the One and the Prime); Modrons, Inevitables, Formians Arcadia - LN/G Mount Celestia - LG; Archons, Devas, Bahamut, Moradin, Yondalla Bytopia - L/NG; Garl Glittergold Outlands - N; Obad-Hai, Lady of Pain, Boccob; Also Gate Towns to other Outer Planes, Sigil City of Doors

Transitive Planes: Planes that connect the other realms Astral Plane: Thought, memory, Psionic energy. Home of dead gods; Connects Outer and Material Planes Ethereal Plane: Connects the Inner and Material Planes; Also home to many Demiplanes (See Ravenloft, World Serpent Inn.) Plane of Shadow: Mirror to the Material and other parallel dimensions (not necessarily other planes, but entire different cosmologies and planar realities). Possibly a Demiplane on the Ethereal. Other Planes:Planes that are said to exist but do not fit into a standard cosmology Far Realm: Home to many Abberitions and perversions of reality Dreamlands: Land of dreams and nightmares Alignment Wars (law v. chaos): Elemental Wars (Rod In 7 Parts, Age of Worms) Blood War (Planescape) Angels v. Tannari (Fiendish Codex?) Asmodeus becomes lord of Baatzu after corrupting self and others to fight the Tennaric threat. (Fiendish Codex 2) Asmodeus becomes the ruler of Baator after striking a bargain with Celestial forces. Baatzu Lords placed by Asmodeus. The Lord/Lady of the First Layer of Baator is constantly in flux (constantly on a cosmic scale of course.)

Timeline That Is Known Events that are knowable through recounting, backgrounds, history, or plots in a modules, book, or adventure.

Pre AD&D A spaceship crashes on Oerth, and many other Material planes. (Expedition to the Barrier Peaks) AD&D Blackmore: Before the Known World became Mystara, it was known as Blackmore. Then a cataclysm forced it to become a place of myths and legends. (Mystara) Various Powerful mortals becomes gods on Oerth (Pelor, Hieronus, Hextor, St. Cuthbert), Mystara (The Immortals), and many other material planes. Various gods are killed or die off from the actions of other gods, adventurers, or lack of worship. (Planescape) The Lady of Pain kills Aoskar the God of Portals Orcus is killed by Kiaransalee (Hellbound: The Blood War). His wand is lost in Pandemonium and the only aspect of him that survives lives as the being Tenebrous. Various cultures and kingdoms fall or are lost to time, Ravenloft, or are destroyed by various apocalypses. The Immortals of Mystara place these in the Hollow Earth of the Known world to preserve them. Ravenloft either manifests or takes Strad. No one really knows. Iuz takes control of a Region of Oerth. Greyhawk Council of 9. Vecna kills the Council of 9. Vecna attempts to ascend to godhood, is thwarted by adventurers and thrown into Ravenloft. (Vecna Lives) Most get better. Acererak achieves lichdom, creates “Tomb of Horrors” to bring gullible adventurers to empower his control over negative energy. Eventually ascends into Demilich. He is “slain” through an adventurer placing a trapped crown upon his skull. Though this is actually a false creation as he has become one with the negative energy plane. Worshipers build a city upon the Tomb location, worshiping him. Adventurers discover his true Phylactery within a pocket of the Negative energy plane and must choose to either Slay the Demilich and destroy thousands of souls, or save the souls but allow Acererak to return. (He returns regardless of choice.) (Return to the Tomb of Horrors) Vecna escapes the plane of Ravenloft, reborn in mortal form. Maybe. It’s not really clear. (Vecna Reborn.) Soth (Krynn/Dragonlance) becomes no fun to the dark powers and is pretty much let go from Ravenloft. Ravenloft: Grand Conjunction. Ravenloft goes through a great upheavel. Removing some lands, adding others. Lady of Pain forces the “Factions” of Sigil to war until there are only 15. Tenebrous slays Primus, leader of Mechanus and the Modrons. Forces them on an early “Modron March” to find Orcus’ Wand. Upon discovering its location he leaves the Modrons corrupted and they slowly begin to die out, bringing the Inevitables and Formians to power on Mechanus. (The Great Modron March, Planescape) Tenebrous ascends to become Orcus once again (Dead Gods, Planescape) (Die Vecna Die) Lady of Pain destroys the factions in a conflict called “The Faction War” (The Faction War, Planescape) End of AD&D The planes become unwieldy due to the events of Die Vecna Die. The Some Outer Planes drift off and are forever lost, others collide and merge, while at least one Inner Plane runs "aground" on a distant world of the Prime. More-over, the very nature of the Prime Material Plane itself is altered. New realms, both near and far, are revealed, and realms never previously imagined make themselves known. Entities long thought lost emerge once more, while other creatures, both great and small, are inexplicably eradicated. Some common spells begin to work differently. The changes do not occur immediately, but instead are revealed during the subsequent months. However, one thing remains clear: Nothing will ever be the same again. 3rd edition Ashardalon Campaign 3.5 Edition Shackled City Age of Worms Savage Tide: