In response to this ask that @vorthosjay received, I said I’d tell you a bit about The Book of the Dead.
The Egyptians themselves didn’t call it the Book of the Dead. They called it pr.t m hrw (peret em heru) - or “Going Forth by Day”. It was a collection of spells that helped the deceased attain their most precious afterlife; the culmination of a text corpus that has its first attested appearance in the Old Kingdom, the Pyramid Texts. These texts evolved through the millennia. In the Middle Kingdom, the Book of Two Ways and the Coffin Texts were the primary guides to the afterlife, and more importantly: they became available to the wider public, not just the king as was the case for the Pyramid texts. The Coffin Texts eventually gave birth to the Book of the Dead.
Because Miriam Lichtheim puts it more succinctly than I currently have the energy for, below I’ll share a quote from Volume II of her outstanding series, Ancient Egyptian Literature.
The Book of the Dead, or, “the coming forth by day”, as the Egyptians called it, was a large compilation of spells designed to bring about the resurrection of the dead person and his safety in the afterlife. (…) It is evident that the Book of the Dead is a book of magic. In all periods of ancient Egyptian culture magic was considered a legitimate tool; and in the confrontation with death and the magical approach attained its most luxuriant growth. That is to say, magical means were not felt to be inimical to piety. (…)
No other nation of the ancient world made so determined an effort to vanquish death and win eternal life. Individual thinkers might increasingly lose faith in the promise of eternal life, and might adopt attitudes of resignation and even skepticism. But the majority appear to have clung to the hope of a bodily afterlife and to a reliance on magic as the means to achieve it. Eternal life had come to be conceived in the most grandiose terms: the dead were to become godlike and join the company of the gods. (1976, p. 119)
Now, the pr.t m hrw isn’t the only ancient Egyptian funerary text in existence. (In fact, it isn’t even one text: no single Book of the Dead contains all 192 attested spells.) It is by far the most well-known funerary text, however. As mentioned in this ask, also over on @vorthosjay’s blog, the dwʕt (duat), or underworld, was divided into twelve hours. The Amduat, “What Is In the Netherworld”, is a funerary text that details these twelve hours, the dangers they represented, and how to traverse these regions of the underworld.
The Amduat, then, was a sort of roadmap to the afterlife, like the Book of Two Ways before it. Like the Pyramid Texts the Amduat was at first only for the benefit of Pharaohs and a very few nobles; in the 21st Dynasty, the use of this text became more widespread.
J. H. Taylor wrote a short but sweet paper on the Amduat of Panebmontu, which you can read in its entirety online. (I highly recommend doing so; it’s great.)
From that paper:
The Amduat narrates the story of the sun’s nocturnal journey beneath the earth, from its setting below the western horizon in the evening to its re-emergence at dawn in the east. There are twelve divisions, each corresponding to one hour of the night. During his passage it was believed that the sun god and his entourage of deities fought and overcame the forces of chaos (embodied chiefly as the giant serpent Apep), and experienced rejuvenation, enabling him to be re-born the next morning. By placing the text and images of the Amduat on the walls of the king’s tomb, it was believed that the dead ruler was identified with the sun god and would himself share in the rejuvenation which the deity experienced. (2016, p. 138)
I do think that while the Book of the Dead may have been the initial starting point for the Amonkhet equivalent because it’s so integral a part of the public’s perception of Egyptian culture, creative would have quickly picked up on the Amduat and used that as their further point of reference.
Because we all know Amonkhet is waiting for the second sun to “rise” and Bolas to be “reborn”.
The final juicy tidbit: Throne of the God-Pharaoh mentions four final hours. The Amduat papyri from the 21st Dynasty onward often only contain the final four hours of the night.
I can only guess, but if what I’m assuming here is correct, creative/worldbuilding went all out for Amonkhet.
