We've done this about three times recently, just sayin'... They were the various peoples and communities, indigenous and foreign, living in the Nile Delta, which at that time was a patchwork of natural and artificial islands. They were nominally under Egyptian rule, but several times revolted and had to be suppressed.
There was no complete "Bronze Age collapse". Certainly there was warfare and a few people shifting about here and there over the course of decades, and it's true that eventually the Mycenaean palace system gave way to other forms of rule. But most of the whole "collapse" thing and "abandonment" ideas stem from the messed-up Egyptian King List, which has been artificially stretched since the 19th century AD to produce great gaps in what would otherwise be coherent historical and archeological records. So all the dates before about 800 are questionable or inflated by as 2 or 3 centuries. Fix all that (which should be easy for anyone not clinging dogmatically to modern ideas), and the "dark ages" go away, along with the need to find some sort of agent for a collapse that never happened.
Does that get you started? Now everyone else will jump in with all the long-discredited and unsupportable wild theories about huge migrations from Greece or Central Europe or Denmark or Fiji sweeping vast civilizations off the face of the planet, only to have everyone suddenly reappear 300 years later with the exact same cultures they had in 1200.
Matthew