It was the time of the great Fall of the Eldar, the birth of Chaos into the physical world as we know it. Far from a moment in history, the strife and growing Eye of Terror stretched out for hundreds of years, and the knowledge of its coming was something foreseen by wise men with their finger on the pulse of time and society.
Still, even with this forewarning, not all who fled the core worlds of the ancient Eldar empire were able to move free of this new zone of carnage. When space tore and demons flooded the material universe, it caught many within its gasped. Besieged by foul beasts, planet, space ship, and craftworld alike fought for its very survival. This was the fate of Iderhra too, which was not quite far enough to avoid being swallowed by the Eye.