An introduction to the cosmological frame of the setting: Aurbis, Mundus, Oblivion and Aetherius, and the competing creation accounts that describe how they came to be.
LESSON 01
The Structure of the Aurbis
Learn the three-part cosmological vocabulary that the rest of the programme depends on.
Aurbis, Mundus, Oblivion, Aetherius
Aurbis is the widest term, naming the totality of the cosmos in which everything else sits. Within it, Mundus is the mortal world, containing the planet Nirn and its continent Tamriel. Oblivion is the collective name for the realms belonging to the Daedric Princes, each shaped by the nature of its ruler. Aetherius is the plane associated with magic, the stars, and the Aedra. A student who keeps these four terms straight will find most in-world theological argument becomes legible.
Sources: TES-MORROWIND, TES-OBLIVION, TES-ESO
Nirn within Mundus
Nirn is the world on which mortals live; Tamriel is one continent of that world, and the one this programme principally studies. Other landmasses are named in in-world sources, but they are described far more thinly and almost always from a Tamrielic vantage point. Magic in the mortal world is commonly explained as Aetherius reaching Mundus through the stars, which is why in-world magical theory and astronomy are so closely entangled.
Compare the traditions that explain how Mundus came to exist.
A shared skeleton
Most traditions in the setting share a rough outline. Two opposed original principles, commonly named Anu and Padomay, stand for stasis and change. Their interaction produces the et'Ada, the original spirits. A figure usually called Lorkhan persuades or tricks a portion of those spirits into making Mundus, an act that costs the participants a great deal of their power. Those who took part become the Aedra; those who refused become the Daedra and retain their power intact.
Sources: TES-MORROWIND, TES-OBLIVION, TES-ESO
Where the traditions diverge sharply
The moral evaluation of that act is entirely unresolved and divides the setting's cultures. Many human traditions treat the making of Mundus as a gift and Lorkhan as a benefactor. Many elven traditions treat it as a catastrophic deception that severed the elves from divinity and condemned them to mortality. The events described are broadly common; the meaning assigned to them is not. This is the setting's clearest example of a dispute that cannot be resolved by finding a better source.
Understand Oblivion as many distinct realms rather than a single place.
Realms shaped by their rulers
Oblivion is not one location but a collection of realms, each belonging to a Daedric Prince and expressing that Prince's nature in its landscape, inhabitants, and rules. The realm of a Prince associated with disease looks and behaves nothing like the realm of a Prince associated with knowledge. Treating Oblivion as a single undifferentiated underworld, on the model of some real-world mythologies, produces immediate errors when reading in-world accounts.
Sources: TES-MORROWIND, TES-OBLIVION, TES-ESO
Contact between the planes
Passage between Mundus and Oblivion is possible but constrained, and much in-world magical and legal literature concerns those constraints. The Oblivion Crisis of 3E 433 is the setting's most prominent depicted instance of those limits failing at scale. Earlier and later materials also describe smaller, more localized incursions and summonings, which suggests the boundary is a maintained condition rather than an absolute wall.
Apply the programme's certainty labels to metaphysical claims.
Why cosmology is the hardest evidence
Nearly all cosmological material in the setting reaches us as in-world testimony written by priesthoods, scholars, and partisans, rather than as direct depiction. No mortal narrator witnessed the making of Mundus. This means cosmological claims sit at the far end of the evidentiary scale: they are extremely well attested as beliefs and very poorly attested as events. Confusing the two is the characteristic mistake in this area.
Sources: TES-MORROWIND, TES-ESO
What can still be said firmly
Some things remain solid. The structural vocabulary of Aurbis, Mundus, Oblivion and Aetherius is used consistently across traditions and across releases. The existence of Daedric realms and the possibility of passage between planes are directly depicted. What is contested is origin, motive and moral meaning, not the present architecture. Students should learn to say confidently what the cosmos contains while remaining candid that its history is told only by interested parties.