The Third Intermediate Period of ancient Egypt began with the death of Pharaoh Ramesses XI in 1077 BC, which ended the New Kingdom, and was eventually followed by the Late Period. Various points are offered as the beginning for the latter era, though it is most often regarded as dating from the foundation of the Twenty-Sixth Dynasty by Psamtik I in 664 BC, following the departure of the Nubian Kushite rulers of the Twenty-fifth Dynasty after they were driven out by the Assyrians under King Ashurbanipal. The concept of a "Third Intermediate Period" was coined in 1978 by British Egyptologist Kenneth Kitchen. The period was one of decline and political instability, coinciding with the Late Bronze Age collapse of civilizations in the ancient Near East and Eastern Mediterranean (including the Greek Dark Ages). It was marked by division of the state for much of the period and conquest and rule by non-native Egyptians. History Twenty-first Dynasty The period of the Twenty-first Dynasty is characterized by the country's fracturing kingship. Already during Ramesses XI's reign, the Twentieth Dynasty of Egypt was losing its grip on the city of Thebes, whose priests were becoming increasingly powerful. After his death, his successor, Smendes I, ruled from the city of Tanis, but was mostly active only in Lower Egypt, which he controlled. Meanwhile, the High Priests of Amun at Thebes ruled Middle and Upper Egypt in all but name. However, this division was less significant than it seems, since both the priests and pharaohs came from the same family. Twenty-second and Twenty-third Dynasty The country was firmly reunited by the Twenty-second Dynasty founded by Shoshenq I in 945 BC (or 943 BC), who descended from Meshwesh immigrants, originally from ancient Libya. This brought stability to the country for well over a century, but after the reign of Osorkon II, particularly, the country had effectively split into two states, with Shoshenq III of the Twenty-second Dynasty controlling Lower Egypt by 818 BC while Takelot II and his son Osorkon (the future Osorkon III) ruled Middle and Upper Egypt. In Thebes, a civil war engulfed the city, pitting the forces of Pedubast I, who had proclaimed himself pharaoh, against the existing line of Takelot II/Osorkon B. The two factions squabbled continuously and the conflict was only resolved in Year 39 of Shoshenq III when Osorkon B comprehensively defeated his enemies. He proceeded to found the Upper