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You got me there, I never knew so many of the 1st - 6th dynasty kings were busy reuniting the 'two Egypts'.

The political history of the old kingdom is little known so it is quite possible that the unity of the two lands was quite fragile for much of this time.

Certainly the initial unification under "Menes" either Narmer or Aha, most likely, appears to have been less than perfect.

It is is known that during the Second dynasty there was a serious crisis with a Pharoah by the name of Persiben adopting has his motif not the Horus hawk but the Set animal. The last Pharoah of the second dynasty had to spend much time crushing rebellions it seems.

Pierre