Roughly 300000 BCE
The Hadesian extinction event marks when the earliest known inhabitants of the Hades system disappeared. Current research estimates that the extinction event occurred at roughly 300000 BCE, but ongoing study of the archaeological record of the lost civilization continues to refine science's understanding of what happened. There are multiple theories of what specifically caused the extinction event. One of the more widely accepted hypotheses is that the Hadesians were wiped out by a devastating interplanetary war. Detractors point to a lack of evidence for technology that could have caused destruction on such a large scale.