This division was consolidated under the XXI Dynasty (c.1069-945 BC), the successors of Herihor and Smendes ruling their respective halves of Egypt from Thebes and Tanis . The two ruling houses (both designated as the XXI Dynasty) seem to have coexisted in harmony, with the Theban priest-kings acknowledging the Tanite pharaohs' superiority. Towards the end of this era, a powerful new dynasty of Libyan extraction was founded by Shoshenk I . This XXII Dynasty (c.945-715 BC) ruled Egypt from Bubastis in the Delta until a rival line seized power in Upper Egypt, precipitating civil war between the Bubastite monarchs and the Theban XXIII Dynasty (818-720 BC), which was further complicated by a brief XXIV Dynasty (727-715 BC) of Ethiopian kings.

 

The lifespan of these four dynasties - termed the Third Intermediate Period (TIP) - is one of the murkiest eras of Egyptian history, yet crucial to the New Chronology hypothesis, as the accepted dates for the New Kingdom hinge on the length of the TIP. Rohl contends that the XXI and XXII Dynasties overlapped for generations, and that the duration of the TIP should therefore be reduced accordingly - with knock-on effects down the line.