When did chaotic leadership and lack of unification leave egypt vulnerable to invaders

Old Kingdom- After the long reign of Pepy II came the 7th dynasty said to be a 70 day length of time with 70 pharaohs reigning. There is a noted change in the concept of how one got to heaven. During the Old Kingdom one got to heaven by the will of Pharaoh. From out of the chaos of the 1st Intermediate Period heaven was available to all those worthy of it. War broke out between various nomes with a short period of kingship residing in city of Herakleopolis before the Theban house overthrew it and established itself as the Pharaonic House of the Middle Kingdom under Mentuhotpe. The delta was mostly depopulated at the end of the Old Kingdom, and this allowed Asians to refill it the Hyksos city of Avaris finds its early beginnings during the 1st Intermediate Period.