The Third Intermediate period is defined by the reign of 21st and 25th dynasty and it is dated by the period around 1078 – 664 BC. Amun’s priesthood seized the reign over the southern part of Egypt at the beginning of this period.The 21st dynasty was founded by Smendes in the northern part of Egypt. The Libyan conquerors seized the power in the Egyptian delta later and their 22nd dynasty ruled over the northern part of Egypt. Gradually they ruled in the middle Egypt as well.
From 22nd to 24th dynasty (945 - 747 BC)
Thanks to Libyan mercenaries, who had been members of the royal army for a long period, the Sheshonk dynasty got to the throne. They established a military dictatorship, but they kept the royal rituals. But the kingdom began to fall apart again, because no descendant of Sheshonk I was able to keep the unity of the land. Egypt fell into smaller areas, which were controled by royal families from big centres such as Tanis, Herakleopolis Magna or Leontopolis.
The 24th dynasty (also called sai dynasty) ruled from 724 to 712 BC. The most significant ruler was Bakenranef (Bocchoris), the ruler of Sais city in the Nile delta. He managed to unify the whole Egypt again, for nine years only. He himself was overthrown in the end.
25th dynasty (747 - 664 BC)
The 25th dynasty (sometimes also called Nubian, Kushite Empire or Ethiopian dynasty) was the firts dynasty, which belonged to the historical period called Late period (some researchers count it among the Third Intermediate period and they count the Late period up to the following 26th dynasty).
Piye – the first Pharaoh of the 25th dynasty – seized control over three quarters of the territory. But his successors were beaten by the Assyrians, who conquered Memphis (Mennefer), the northern part of Egypt and plundered Thebes (Waset).