The Convergence

The Convergence was an event on a planar scale that happened five hundred years ago.

The Event
Five hundred years ago the four Material Planes collided, somehow. This event killed untold numbers of people through both the initial impacts but also the outpouring of planar chaos that followed.

The Planes reacted by stitching themselves together where the impacts happened as a solution to stop the outside influence of the Astral Sea and the Elemental Planes. This negative space formed between the Material Planes was what is now known as Bridges. It is during this event that the Iyari were born.

Aftermath
The drama of this event shook the entire planar system and caused knock on effects to the other planes in the system. Many of the outer planes were shaken free of their aligned bounds which in turn caused the destruction of many celestial powers. The former order of things changed and seemingly the gods died.

Many flocked to the eventual City to seek some sort of godly comfort from the Iyari, who many deemed the new gods. This is something the Iyari deny avidly though.