Cosmology

The following is an excerpt from a scroll on cosmology from the College of Mages at Selemlis.
It seems that the beginning of all things is not something that is given for the lesser races to know. The Dragons claim to be the first races, and certainly they are the embodiment of The Materium, but the Giants claim that they are the makers and none of The Materium was made that was not made by them (although they themselves are part of The Materium. The Giants worship but a single deity, who they refer to as the Creator or Demiurge, and who they say created the cosmos and predated even the Lords of Creation who are his servants. The Giants say that the cosmos itself was built by an order of giants that are now extinct called the Time Giants, who built with time itself, and that the material plane was created from the body of the first and greatest of dragons. It was the Faerie though that created The Immaterium (or were created by The Immaterium), for they are places of pure imagination and spirit. It was only when the Time Giants brought the solidity of the Dragons together with the imagination of the Faerie that time and change could begin, and that the Lords of Creation came into being.
What is certain is that the three elder races of Giants, Dragons and Faerie are as ancient as the cosmos, unlike the younger or lesser races. The lesser races are only native to the material plane, and lack the level of control over the material plan that the elder races have, but at the same time are less affected by the material plane. All the elder races draw some of their power from the material plane.
Dragons of course famously require hoards of the most precious substances. The ignorant think that this is because they are greedy, but it is actually because they need this concentration of precious materials to maintain their physical presence.
The faerie that dwell partially in the material plane (no faerie dwell entirely in it, but some do entirely dwell in The Immaterium) draw power across from The Immaterium. The amount and type of power that they draw across depends on their strength and status, which is why seasons in elven realms are dependent on the nature of those dwelling there - when elves are young and dynamic, it will be spring or summer, but as they age and become more jaded, the seasons will fade to autumn or finally winter. This also explains why faerie realms are often larger than they might appear from outside - energy from The Immaterium is actually causing The Materium to stretch to absorb it.
The Immaterium is the source of magic for Faerie, and also for Wild Magic Sorcerers. It is also the source of magic for wizardly spells of the conjuration, illusion and enchantment schools. The Materium is the source of magic for clerics, druids, paladins, rangers and wizardly spells of the abjuration, evocation and necromany schools. Diviniation spells depend on the source of the divination. Transmutation is blending magic from both The Materium and The Immaterium.

Material Plane

The sages teach us that each decision in time has many outcomes, and for each of these outcomes, a new material plane comes into being. Thus in the beginning there was but a single material plane, but with time, there are now an almost infinite number of them.
One result of this is that the same deities are found on almost all of the material planes. It is only the youngest deities that are only found on certain worlds, because they were created after those worlds branched off from other worlds.

The Ages of the World

The known ages of the world are: The dragon age, which is conventionally regarded as having lasted for 10,000 years, although it seems that time was less stable and linear back then. This was the era when the material plane was created, but was also a static era, as there was as yet little involvement of the Faerie in the material back then. This ended with a series of wars as the Faerie sought to impose themselves into the material plane from the Feywild and Shadowfell.
The Bright Empire, which lasted for 5,000 years. The elves created the first empire, having created the lesser races to serve them.
The Dark Empire, which lasted for 1,000 years. Gradually the elves became corrupted, and enslaved the lesser races, and even some of the giants and dragons. The Dark Empire ended in a cataclysm called the Sundering, when their heartland sank beneath the Inner Sea, leaving the two continents of Vanareon and Ardaling.
The Twilight Age, which lasted for 2,000 years, when scattered remanants of elves formed the High Kingdom, and tried to rebuild the Bright Empire.
The Peloth Empire, which lasted for 1,353 years. This was the first Human empire, centred on the city of Peloth in Perin-Galath.
The Age of Strife, after the fall of the Peloth Empire to barbarians from Acoria. This lasted for 823 years, until the founding of the Ilsig Empire.
The Ilsig Empire, which lasted for 1,108 years, until it was supplanted by the Rankan Empire.