The book of Genesis records the story of Joseph in chapters 37 – 50. This is as many chapters as the story of Abraham occupies (chapters 12 – 25).
In all of these chapters, however, the name of Pharaoh is not recorded. The name of his “Captain of the Guards” is there, but not the name of Pharaoh himself. Interestingly enough, the Pharaoh at the time of the Exodus in Exodus 1-15 is not given either. Both are simply called Pharaoh.
In the lists of Pharaohs of Egypt, there are many “dynasties.” A “dynasty” is a group of rulers who rule in succession from parent to child. Sometimes dynasties simply die out, but usually a dynasty ends when a palace coup or other disaster overtakes a particular Pharaoh – sometime by being overthrown by foreign rulers.
There was a dynasty known as the Hyksos rulers of Egypt who were foreign to Egypt. This group had overpowered the Egyptian family of Pharaohs and ruled for many years before being ejected. Following is an excerpt from the International Standard Bible Encyclopedia article on “Egypt,” as found in http://www.e-sword.net.
The Semitic tribes had long been filtering into Egypt, and Babylonian Semites even ruled the land until the great migration of the Hyksos took place about 2700 bc. These tribes were ruled by kings entitled “princes of the desert,” like the Semitic Absha, or Abishai, shown in the tomb of Beni-hasan, as coming to settle in Egypt. By 1700 bc the Berbers who had adopted the Egyptian civilization pressed down from the South, and ejected the Hyksos rule. This opened the most flourishing period of Egyptian history, the 18th Dynasty, 1587-1328 bc.
The Hyksos were contemporaries of Abraham (c. 2000 BC), and were ejected from Egypt about 1700 BC, which would have been after the death of Joseph. It is likely the Hyksos Pharaohs were in power during the lifetimes of both Abraham and Joseph.
Note that these were Semitic tribes, that is people descended from Shem (see Genesis 10). The Egyptians were descendants of Ham. Thus, the Hyksos were relatives of the Hebrews, which could help explain the warm reception Pharaoh gave to Joseph and his family. This would help, also, to explain that Genesis 39:1 observes that Potipher (the captain of Pharaoh’s guards) was an Egyptian. This statement makes more sense if the reader realizes that Pharaoh himself was not an Egyptian. (It would hardly be remarkable that the head of the Secret Service guarding the American President is an American, would it? It would only be note worthy if he were not an American.)
Again, when Joseph’s family moved to Egypt, Joseph instructed them to tell Pharaoh that they were shepherds and that they would be given the land of Goshen, the best part of the country, “for all shepherds are detestable to the Egyptians” (Genesis 46:34).
Why did Pharaoh give the best part of Egypt to the Hebrews when the Egyptians hate shepherds? Well, the Hyksos are also sometimes called “The Shepherd Kings.” As Semites, they were shepherds. As foreign rulers, they were hated by the Egyptians – who then hated all shepherds! After Jacob and some of his sons met with Pharaoh, he asked Joseph to put some of them over his own herds (Genesis 47:6). This also suggests that Pharaoh was not one of the Egyptians who hated shepherds, but that he had herds of his own that needed experienced herdsmen to care for them – who were scarce in Egypt.
Exodus 1:8 says that “a new king, who did not know about Joseph, came to power.” This is not just a son or grandson of the king whom Joseph served – but a new dynasty. This would be, if my thesis is correct, the Berbers who came in from the South (the upper Nile region) about 1700 BC or roughly 150 years before Moses led Israel out of Egypt.
This, of course, comes from secular sources, not from the Bible. These do present interesting coincidences with the Biblical account of Joseph and Moses, however.
Hopefully this information, sketchy as it is, will be of some assistance to you.