In the vignette that illustrates chapter 125 of the Book of the Dead, the deceased is led into the Hall of Two Truths and their heart, seat of conscience and memory in Egyptian thought, is placed on one pan of a balance. On the other pan sits the feather of Ma'at, order and truth given the shape of an ostrich plume. Anubis positions the scale and reads it; Thoth, ibis headed scribe of the gods, records the result; and Ammit, part crocodile, part lion, part hippopotamus, crouches beside the scale to devour any heart that fails, ending the deceased's chance at continued existence. A heart that balances against the feather is judged true of voice, and its owner passes on to the fields of Osiris. The scene appears painted or written on papyri placed with the dead from the New Kingdom onward, and its details, the exact gods present, the wording of the accompanying spells, vary between copies while the central image, heart against feather, stays constant across more than a thousand years of use.
Raymond Faulkner's translation of the Papyrus of Ani preserves one of the fullest illustrated versions, the copy against which most modern accounts of the scene are checked. Later periods added variant vignettes, some showing a baboon, a form of Thoth, perched atop the scale's pivot to signal that the reading is honest, a detail absent from the earliest New Kingdom copies.