The Old Kingdom, Middle Kingdom, New Kingdom and their conflicts.
The Old Kingdom [2575 BCE - 2150 BCE]
The Fall of the Old Kingdom and the First Intermediate Period
The Middle Kingdom [1975 BCE - 1640 BCE]
This was a time when Egypt had a strong central government and a prosperous economy. This time is most famous for when the pyramids were built. This includes the Pyramid of Djoser and Great Pyramid of Giza.
The Fall of the Middle Kingdom and the Second Intermediate Period
The governors (nomarchs) became so powerful that they started to ignore the rule of the pharaoh. Egypt also suffered from drought and famine, then the central government collapsed and Egypt broke into several states. The first intermediate period lasted around 150 years and was a time of civil war and chaos.
The New Kingdom [1520 BCE - 1075 BCE]
Around 2000 BCE, Mentuhotep II became king of southern Egypt. He attacked the north and reunited Egypt under one rule, thus the period of the Middle Kingdom began. The capital was moved to Thebes and, from that point on, would remain a major religious and political center. A new type of sculpture became popular and writing and literature developed as well.
The Third Intermediate Period and the Late Period [653 BCE - 525 BCE]
A group of kings in northern Egypt split from southern Egypt. The country fell into disarray and the Middle Kingdom collapsed. The second intermediate period is most famous for the the Hyksos who invaded and ruled Egypt from the capital city of Avaris.
The New Kingdom was the golden age of civilization for ancient Egypt and saw some of Egypt's most famous and powerful pharaohs. During this time was when Egypt conquered the most lands. At the same time, they expanded trade with many external nations and used gold mines to gain great wealth and import luxury goods from around the world. The pharaohs used this wealth to built massive temples to honor themselves and the gods.
Multiple wars, combined with drought and famine, caused unrest throughout Egypt. Corruption and fighting in the central government became worse. Egypt was no longer united. The third intermediate period saw a divided Egypt under attack from foreign powers. And thus, the Late Period was a time when Egypt was under foreign rule. They were conquered by the Persians and when the Persian empire crumbled, Egypt was led by a Greek, Ptolemy.