The so-called Second Intermediate Period is a century of time when Egypt was divided into two separate political powers exercising authority over Egypt including one foreign power that the Egyptians called "hekaw-khasut" in their writing and whom we call the "Hyksos". This essay will briefly explore what caused this period of Egyptian history and it's impact on reunification and Egyptian culture.
The "Hyksos" were a non-specific Asiatic peoples who moved into Egypt during the 18th century bce. Their identity is still debated ranging from wandering Hebrews to Palestinians nobility to a hodge podge of different Near Eastern peoples who found the Delta provided livelihoods. The Egyptians themselves depict these foreigners as invaders though ultimately they were not so much expelled or destroyed as absorbed into Egyptian society two centuries later.
This "invasion" according because of the weakness of the 13th and 14th Dynasties. The internal weakness of the ruling family came from reigns which were far too long and which left no viable male heir. By the time the 12th Dynasty ended with the female Pharoah, Sobkneferu, the 13th Dynasty was threatened by other nobility in the Delta, specifically in the Delta region. Political instability in the Delta, also called Lower Egypt, allowed these foreign invaders to gain control of Avaris, which would be their capital for a century, under the Manetho or Turin category of 15th and 16th Dynasties. Note however that the Hyksos artifacts and references are found a century before their political control suggesting that theirs was not so much invasion as it was the eventual growth of a foreign population on the Nile and the inability of the native nobility to protect the protection and direction they had in the past.
Once the 14th Dynasty failed to produce any viable heir, a new dynasty arose in Thebes, foreshadowing later problems Pharoahs would have with Thebes. Evidence in tombs and legal documents suggest that the 17th Theban Dynasty and the Hyksos had good diplomatic relationships perhaps reenforced by marriage. The Hyksos in the Delta continued to control that region until they were driven from power though not from the community by Ahmose, the founder of the 18th Dynasty. For one century then power in the North was controlled by this foreign group while the South was tossed from one dynasty and city to another.
The Hyksos themselves continued many of the political and religious practices of the native Egyptians. They did introduce a new style of architectural in fort-like buildings and their own pottery designs. They also elevated the god Seth to a place of honor perhaps to compete with the cult of Osiris who was popular in Upper Egypt or the Nile Valley. They also imported several gods and goddess from the Near East ranging from several different cultures along side traditional Egyptian deities. In terms of technology, the Hyksos seem to have brought the harnessed horse chariot to the region, a vehicle that would be very important for the advance of the Egyptian Empire in the "New Kingdom". They also introduced new techniques of metal working, bronze, that appears in their armor.
Both the native Eygptian dynasties and the Hyksos carried on diplomatic relationships with the Near East and the Thebans claim to have extended their authority further into Egypt. Any so-called Civil War during this period came near the end when one son of the 17th Dynasty decided he'd had enough and declared his independence, using the claim of foreigners and the need for unification to promote himself.
Thus our image of the Hyksos and the Second Intermediate Period are colored by the propaganda from Ahmose and the 18th Dynasty. We need to balance their military and political needs with closer attention to the Delta artifacts which strongly suggest that these foreigners were not invaders at all but rather resident aliens who were able to gain power in one region during a time of internal instability.