Coffin Texts
Parts of the corpus of Pyramid Texts were passed down into the Coffin Texts, an expanded set of new texts written on non-royal tombs of the Middle Kingdom, some retaining Old Kingdom grammatical conventions and with many formulations of the Pyramid Texts recurring. The transition to the Coffin Texts was begun in the reign of Pepi I and completed by the Middle Kingdom. The Coffin Texts formed the basis for the "Book of the Dead" in the New Kingdom and Late Period. The texts would resurface in tombs and on papyri for two millennia, finally disappearing around the time that Christianity was adopted.