With the ancient Egyptians the rising and sitting of the sun showed the death and rebirth and victory over the forces of the night of their god Re. We can find depictions of the rituals on the walls of Egyptian temples and tombs that show the pharaoh, who was the divinely appointed representative of the sun god, receiving from Amon the gift of immortality. The pharaoh would receive this gift of immortality in the form of an ankh, the hieroglyphic symbol of life.
We find in "The Hymn to the Aten" (ca 1352-1336 B.C.E), "You rise in perfection on the horizon of the sky living Aten, who started life. Whenever you are risen upon the eastern horizon you fill every land with your perfection." He ancient Egyptians are reminded that Aten started life. That with this hymn they shouldn't forget why they are here, because it was Aten that gave them life. That Aten rose from the east and that his perfection filled every land. That Aten was the only reason that things lived because of his perfection crops grew and the Egyptian people were alive. According to this hymn Aten even took care of them in their mother's womb.
We can also track ancient Egyptian history through hieroglyphic symbols left on papyrus. We know the start of each dynasty and when each one ended. We also know from tombs and temple ruins what pharaoh ruled during those dynasties.
In keeping these records and preserving the pharaoh's bodies they would ensure that the pharaoh would be able to join his rightful place in the heavens as a god. This...