By the way, Paul, my ancient history's not A1: were the Hyskos upper Nile 'Sudanese' people?
Hyksos (my initial bad spelling was "Hyskos", duh!) supposedly meant "rulers of foreign lands, once mistranslated as "Shepherd Kings". They came from the North-East, what later became known as Canaan. The consensus is that they were a semitic speaking group of nomads, though likely containing some other linguistic/ethnic groups as ancient 'hordes' regularly had a mix (I don't care that he is a Mongol and conquered us, there's loot to be had, let's join).
The first started drifting in starting about 1800 BCE and by around 1650 BCE overthrew the native dynasty. They were finally expelled about 100 years later. Their chief god Baal became associated with the Egyptian god Set and in Egyptian eyes Set went from a good god to a bad one. While modern eyes may view that period as an invasion, just as plausible is that they started as traders and possibly food refugees and later, in combination with more and newer arrivals, took opportunistic advantage of the weakness of the native dynasty to establish their own state. They seemed to have introduced improved bows, war axes and the horse to Egypt, along with other technologies, animals and crops. As horses then were still too small to carry men they were used to tow chariots. What we think as the archetypical Egyptian mode of warfare, bow armed chariotry, was actually a foreign development.
The Hyksos have been the subject of much speculation, some saw their intrusion as the basis of the Hebrew stories about Joseph and Moses
et al. One could speculate that the enslavement of the Hebrews as a result of an Egyptian war of liberation or of paranoia from the earlier invasion. Of course, like ideas that Moses was Akhenaten, such speculation should be dipped in salt, deep fried and consumed as a very light, amusing snack. Such tales may have some tiny grain of truth transmitted by folklore, but that's about the limit. Most of the Hyksos era is unknown because the Egyptians erased as much related records as they could,
a la 1984.
https://en.wikipedia.org/wiki/Hyksos