Second Intermediate period 1782–1570 BC
Why did Middle Kingdom fall?
The rulers of the 12th dynasty were the most powerful in the Middle Kingdom. But queen Sobekneferu died without an male heir to the throne. So, this dynasty ended with her and must have let to a power struggle to the throne.
13th dynasty ascended to the power but it was not as powerful as the 12th dynasty was. And it diminishes furthermore as the time went by until a power in the north conquered their territories.
Kingdom in the north: Senusrat III, the most powerful ruler of 12th dynasty, had established a port city in Avaris, in the lower i.e north Egypt. Gradually, people from Asia, especially Semitic in origin, started migrating in this region and grew in wealth and power. Later they challenged the Egyptian ruler of 13th dynasty at the centre. These Semitic rulers in the north founded the 14th dynasty and ruled the lower Egypt from their capital Avaris. Later, another foreign power called Hyksos conquered the territories of these 14th dynastic rulers and established the 15th dynasty.
Kingdom of Kush: King Senusrat III led military campaigns against Nubia in the south of Egypt and fortified its border to secure it from any assault from farther south. He established a garrison there for this purpose. But gradually as the power of the central kings diminished, they stopped sending the resources to the garrison for its maintenance. So this border from the south got dissolved over a time and a power from the south, called Kushites, seized the region.
Abydos Dynasty: This dynasty ruled a local territory from the upper Egypt and was contemporary to the 15th and 16th dynasty.
All these powers broke the Egypt into at least four territories and thus started the second intermediate period.
The Second Intermediate period includes a part of 13th dynasty, 14th, 15, 16th and 17th dynasties.
13th Dynasty: As for the 13th dynasty, the records written in this period diminished with the diminishing power of the king. Thus nothing is sure how this dynasty ended.
14th Dynasty: 14th dynasty was founded by Semitic rulers and established their capital at Avaris. Some Egyptologist believed that they settled in the north Egypt at the time of the last ruler of the 12th dynasty, queen Sobekneferu. But other believed that this dynasty started around the mid of 13th dynasty and gradually grew in power to the point that they challenged the Egyptian ruler of 13th dynasty and broke away the north Egypt from the south.
During the reign of 13th and 14th dynasties, they were struck by the prolonged famine that may have destabilized the both kingdoms, i.e 13th and 14th dynasties.
Then Hyksos who emerged from Syria and Palestine region, completely defeated the 14th dynastic ruler.
15th Dynasty: Hyksos defeated the 14th dynasty king in Avaris and established their kingdom and founded 15th dynasty. They invaded the region of 13th dynasty ruler and conquered their territory.
16th Dynasty: After the defeat at the hand of Hyksos, the Egyptian ruling class moved further south from Thebes and established their capital at Itj Tawi. Manetho, a third-century BC Egyptian Priest put them in the 16th dynasty. These Egyptian rulers continued the wars with Hyksos and lost their territories to them. Then Hyksos even conquered Thebes.
Some historian assumed that 16th dynasty was the vassal state of Hyksos, while others believed that they were independent rulers but nothing is certain about their status. Though now historian put this dynasty a separate ruling class, not a vassal state.
17th Dynasty: This dynasty comprised of Theban rulers and was the contemporary to the Hyksos in the north and the successor of 16th dynasty. The rulers of this dynasty fought with Hyksos.
King Seqenenre Tao of 17th dynasty died in the battle while perhaps fighting with the Hyksos. His son, Kamose, who was the last ruler of this dynasty, fought with the Hyksos and boasted that he destroyed Hyksos capital Avaris.
But Archeological findings suggested that it was Ahmose I, who ascended to the throne after the death of his brother, Kamose, and destroyed it. Ahmose I finally defeated the Hyksos and ousted them from the Egyptian territories. Hyksos went back to Syria and Palestine region and nothing was known as for what happened to them.
Ahmose I, after unifying the lower Egypt to his territories, turned towards the south in Nubia. He conquered back the territories the former Egyptian kings held. And thus united Egypt under his power and started the New Kingdom.