In River God, Pharaoh Mamose is killed in battle against the Hyksos, led by King Salitas, and the Egyptians are driven into exile along the upper reaches of the Nile.

The name Hyksos is derived from an Egyptian phrase meaning 'rulers of foreign lands'. They were a mixture of nomadic tribes from the Eastern Mediterranean countries and groups of wandering Semites who had long traded peacefully with Egypt and settled in the Delta region, integrating with the Egyptians and rising to high positions in the government.

The Hyksos invaded the Nile delta in huge numbers in around 1650 BC and with the help of those already settled there they brutally overthrew the rulers of Lower Egypt,[1] burning towns and villages while fortifying the city of Avaris as their capital and founding their own dynasty, the 15th dynasty, with their leader Salitis as the first king.

The Egyptians could not stand before the Hyksos because the Hyksos possessed superior weaponry, such as bronze battle axes and the composite bow, made from wood, horn and sinew, and much stronger than the all wood bows of the Egyptians. Most devastatingly though, the Hyksos came 'swift as the wind', because they had the horse and chariot, neither of which were known to the Egyptians – indeed the Hyksos were responsible for introducing the horse and the wheel into Ancient Egypt.

The Hyksos slowly spread south along the Nile, but they never reached much beyond Thebes, and Upper Egypt was never under threat.

The Hyksos sowed the seeds of their own destruction. The Egyptians learned how to fight with the horse and chariot and how to use the new weapons introduced by the invaders. Around 1550 BC, a young Pharoah called Ahmose led an army out of Upper Egypt, defeated the Hyksos in battle and sacked Avaris, bringing 100 years of Hyksos rule to an end and liberating Egypt from the 'foreign rulers' forever.

The Hyksos were not all bad. As well as their advanced weaponry, they brought with them many non-military innovations that would benefit Egypt considerably. They cultivated new fruits and vegetables, and increased trade with the islands of the Mediterranean using superior keeled ships, far more stable and seaworthy than the basic Egyptian felucca. They introduced the potter's wheel, which led to improvements in pottery, the vertical loom, which increased the production and quality of linen products, and developed new techniques in bronze working.

After 100 years of Hyksos rule, Egypt was less insular, more advanced technologically, and had a well-trained and well-equipped army, which they were able to use to expand their empire to its furthest extent. Under the New Kingdom that followed the Hyksos, the Egyptian Empire reached its zenith.