19th Dynasty Interregnum

At the end of the 19th Dynasty, just following the Santorini eruption, a number of pharaohs laid claim to the throne. The major participants were Merneptah in the north, and his sons Seti II and Siptah in the south. Others were Shoshenq I, who claimed the territory of Bubastis, and Smendes I in Tanis. This period lasted from 765 to 759 B.C.

In 765 B.C., a volcano in the Mediterranean exploded, causing ash fallout and effects that lasted for decades. This would become known as the Santorini eruption, and it fractured Egypt along with other ancient empires. Merneptah was the pharaoh at the time, and people probably saw this event as proof that his rule was no longer favored by the gods. His sons Seti II and Siptah thus split apart from their father and took control in Thebes and Upper Egypt.

Seti II was the original ruler of this area, following 765 B.C., but Siptah quickly also laid claim to the throne. Similarly, their half-brother Amenmesse took control while Seti was absent from his territory (764 to 762 B.C.). Seti II and Siptah ruled together for six years (765 to 759 B.C.), and Seti's wife Twosret claimed to be ruling independently as well during 760 B.C.

This chaos came to an end when Setnakhte, the first pharaoh of the 20th Dynasty, ascended to the throne. He managed to unite the quarreling descendants of Ramesses II and ruled in Pi-Ramesses for two years. As Seti II was the first and last surviving pharaoh of this period of interregnum, Setnakhte considered him his predecessor.

The evidence for the revised history can be found at Displaced Dynasties. Evidence pertaining to this period of Egyptian history can be found here.