High Priests of Amun
Another reason why there is much debate is because next to the conflicts between Lower and Upper Egypt that existed, there were now also conflicts in the Delta itself. Part of these conflicts were succession struggles, but another part of it were High Priests of Amun at Thebes, who for a period during the Twenty-first Dynasty effectively ruled Upper Egypt, despite not being regarded as a separate dynasty (however, some did become pharaoh as part of a dynasty, like Psusennes I). Although their power declined after the Twenty-first Dynasty, the High Priests of Amun remained powerful and influential people, and marriages into the royal family were not unusual. As a result, multiple reigns within the Twenty-third Dynasty as well as between the Twenty-second and Twenty-third Dynasties overlap. This is because some members of the Twenty-third Dynasty reigned as independent kings (like Harsiese A), and as a separate dynasty after Osorkon II’s (of the Twenty-second Dynasty) death. Some historians argue that the Twenty-third Dynasty started with Takelot II, and consider Pedubastis I as a separate independent (and short lived) part of that Dynasty. Others consider Takelot II's line as a separate independent part of the Twenty-second Dynasty, and consider Pedubastis I's short lived line as the Twenty-third Dynasty.