In the late sixth millennium BC farming villages appeared, as did rock art in some of the region's caves, and the following two millennia saw the gradual formation of small states.After 4000 BC, thanks to the sudden desiccation of the grass plains of the Sahara and an influx of people towards the Nile, there was a substantial increase in population, and villages sizes increased accordingly.
Highly interesting new research that was published in the Proceedings of the Royal Society in 2013 established what was possibly the most accurate timeline for early Egypt.
Previous records had suggested that the pre-Dynastic period, a time in which early groups began to settle along the Nile and farm the land, began in 4000 BC.
One of these rulers was the first to unite the whole valley, from the first cataract near the Nubian Desert to the Mediterranean, as a single kingdom in about 3400 or 3100 BC.
There are two main schools of thought regarding the dating of Egyptian dynasties.
None of them are entirely conclusive or widely accepted.