Mentuhotep II of the 11th dynasty was only king of Upper and Lower Egypt for part of his reign – at a time when the Israelites were in Egypt.
Mentuhotep II was the 5th Pharaoh of the 11th dynasty which as based in Thebes. The son of Intef III. He reigned for 51 years. Around the 14th year of his reign, he defeated the Herakleopolitans (10th dynasty) and was able to consolidate his reign. Around his 39th year on the throne he reunited Egypt. He is considered by many to be the first pharaoh of the Middle Kingdom.
Manetho’s statement that the 11th Dynasty consisted of 16 kings, who reigned for 43 years is contradicted by contemporary inscriptions and the evidence of the Turin King List, whose combined testimony establishes that this kingdom consisted of seven kings who ruled for a total of 143 years.
The 11th dynasty seem to have originated with a Nomach from Thebes “Intef the Great”. His son Mentuhotep I is regarded as the first king of the dynasty. Intef II, son of Mentuhotep I, was the first king of the dynasty to lay claim to ruling Upper and Lower Egypt but only managed to take as far North as Abydos where he came into conflict with the 10th dynasty kings of Herakleopolis. His son Intef III was the father of Mentuhotep II.
Ancient Egypt had 42 provinces or ‘Nomes’ as they were called. These were divided into those of Upper Egypt and those of Lower Egypt. Each province or ‘Nome’ had a Govenor or ‘Nomarch’.
Dynasties refer to a line of rulers who were related to one another. Dynasties often ran in parallel in different parts of the country. Potentially, there could be 42 dynasties running in parallel at one time in Egypt if each Nome had a series of leaders from the one family line.
The 11th dynasty, based in Thebes, was contemporary with dynasties in other parts of the country. In particular, the 9th and 10th dynasties, based in Herakleopolis, often referred to the as the First Intermediate Period (when Lower Egypt had no King), were contemporary with the 11th dynasty. The 9th and 10th Dynasties lasted only 20 years and followed the sixth dynasty which was also contemporary with the 11th dynasty but in a different part of the country (Memphis).
The principal dynasties that were recorded by Manetho refer to the families that ruled Upper and Lower Egypt or both (ie Kings).
Mentuhotep II defeated the Herakleopolitians in the 14th year of his reign. This ended the First Intermediate Period when Lower Egypt had no King. Egypt was not unified, however, until the 39th year of his reign.
At what point did Mentuhotep II become the King of Upper and Lower Egypt? Was it by force when he defeated the Herakleopolitians or was it in the 39th year of his reign when Egypt became unified?
Assuming that there was continuity of the Kingship, the chronology of Egypt would be considerably shorter if the dynasties were aligned according to when a change of Kings occurred without shortening the dynasty as there would, no doubt, be much more overlap of dynasties.
When Pharaohs (Kings) took the reign by force, they would subjugate the other Nomarchs, killing those who would not submit and allowing those who did to continue their dynasty in parallel.
After all, there were 42 Nomes and 42 Nomarches and potentially there could have been 42 dynasties running at one time. Only the major dynasties were recorded by Manetho. These were the more important dynasties in which a Nomarch ruled Upper or Lower Egypt and sometimes both Upper and Lower Egypt. What’s more, these Nomarchs could have reigned considerably longer than the period that they wore the crown of Upper or Lower Egypt or both. Failure to understand this would grossly prolong the Egyptian Chronology.
There may have been times that Egypt had no native king to unite it’s 42 Nomes. This was most likely the case during the first intermediate period even though it was contemporary with the 11th dynasty. The second intermediate period was a time when Lower Egypt was ruled by foreign invaders from Arabia (the Hyksos).