The Collapse, also called The End, the Eschaton, the Skyfall, the Big Crush or many other regional euphemisms refers to the apocalyptic events of year 0 of the Era of Collapse.
It is believed that the Collapse was caused by the hubris of the people of Tinris. The Era of Prosperity's closing years were filled with arguably clear messages and omens that are apocryphally attributed to the Paton deities. What few records remain of such warnings point to a period of roughly 50 years during which the suns began to dim, domesticated animals began to howl at erratic times, communication between previously peaceful factions began to grow tense to the point of open hostility and many other such factors. Yet the course of civilization continued unabated.
According to world-renowned eschatologist oracle Tain Darkspeaker, it was on Calibration of what would very soon become year 0 Collapse that Ilfandra called a convocation of Patron deities and put forth a repeal to the Law of the Orbits. With this Law repealed, the Planar deity Ugozte the Unmaker was no longer bound. In the span of two days, His unnamed pupil called forth a barely subluminal shower of massive stellar rocks to impact Tinris.
Many such projectiles were caught within the complex gravities of Adris and Tesulild, being torn asunder and forming Tinris' planetary ring. Others bypassed these natural barriers, as the repeal allowed, and struck the surface of the planet. Coastlines rushed inland as the water levels rose, crater lakes formed at the sites of major landfall impacts, entire cities were leveled, the planet's magnetic poles shifted and nearly one billion people perished within the first ten days. Within a year, the death toll stood at two billion people, a full two-thirds of the world pre-Collapse populace.
In the wake of such great devastation, society splintered. Wars raced across the continents as many cultures and subcultures sought to blame each other. Carisar was sacked in the year 159 and with it the basic infrastructure of Orytonian Halfling civilization fell in upon itself.
What few Elves lived outside of the Twilight Archipelago were killed, sacrificed or otherwise savaged as popular opinion became that it was they and their Patron Moondragon that were clearly responsible - a bias lingering still fresh in the minds of the Halfling people from the Era of Conflict. Those few that survived pulled back to the Archipelago and closed their borders.
The Tinris World Navy was scuttled to its very last ship. In part this was due to the shifts in navigability resulting from the pole shift and the subsequent failure of the World Navy to be able to properly render aid. The greater part, however was a matter of resource management.