The Sundering

The Sundering was a major magical catastrophe that began 452 years ago and lasted a century. Although the exact cause is unknown, it resulted in all magic and spellcasting to fail. Although divine granted magic still worked, it was weaker and could not act as intended.
for 100 years the effects of this event reverberated throughout Vaelun. Being less magically inclined the Dwarves were the least affected, however they did close their borders during the troubles further south.
the Rivellian empire was a magocratic monarchy, during this era the death of the empire caused anarchy as without magic there was no clear successor. the empire splintered into a dozen warring states, four of which have survived to the modern day and the region gained the name The Shattered Realm. This event is why the catastrophe is called the Sundering in human tongues.
For the Elves, the most attuned to the weave, it was as if part of their very being was missing. During this time something happened that caused demons and fiends of other planes to emerge from planar gates in the lands of the Nuneian Theocracy. After a long bitter struggle the elves were victorious although many of their cities were razed and abandoned.