Ra's daily journey across the sky and through the underworld supplied ancient Egyptian kingship with its central religious justification, a theology that reached its most developed form in the syncretic figure of Amun-Ra, formed when the originally separate Theban god Amun absorbed Ra's solar identity as Thebes rose to political prominence during the New Kingdom, distinct from the older Heliopolitan fusion of Ra with the creator god Atum. As Amun-Ra, the god became the supreme state deity of the New Kingdom, worshipped at the vast temple complex of Karnak, and pharaohs across this period styled themselves specifically as Amun-Ra's son and earthly representative, borrowing the sun god's own unbroken daily cycle of death and rebirth as a template for royal continuity and legitimate succession. Egyptian funerary hymns preserve this royal register directly, praising Ra's nightly victory over the serpent Apep and his guaranteed return each dawn as the pattern every dead king, and by extension every dead Egyptian, hoped to follow into their own rebirth. This solar kingship theology proved remarkably durable, surviving political upheavals, foreign rule and even the brief but dramatic attempt by the pharaoh Akhenaten to replace the wider solar cult with exclusive worship of the sun disc Aten alone, a reform his successors reversed almost immediately, restoring Amun-Ra and the older solar theology of kingship to its central place in Egyptian state religion within a generation of his death.