The Duat is the ancient Egyptian underworld, but it is better understood as a nocturnal passage than a static place. Every night the sun god Ra descends into it, sailing his barque through its twelve regions, one for each hour of the night, to be regenerated and rise again at dawn; and the dead must make the same perilous journey to reach the paradise of Aaru.
The Duat is a realm of gates and guardians, demons and lakes of fire, its geography mapped in extraordinary detail by the funerary texts painted on tomb walls and coffins, the Book of the Dead, the Amduat ("that which is in the Duat"), the Book of Gates, which functioned as guidebooks for the deceased, supplying the spells, passwords, and names needed to pass each obstacle safely. Its culminating trial is the weighing of the heart in the Hall of the Two Truths, where the heart is balanced against the feather of Maat before Osiris and forty-two assessor gods; the unworthy heart is devoured by the monster Ammit, ending the person's existence entirely, while the justified pass on. The Duat expresses a profound Egyptian idea: that death, like the nightly darkness, is a passage to be navigated with knowledge, and that rebirth, of the sun and of the soul, is won each time through trial.