Short answers, pulled from the story.
French archaeologist Gaston Maspero discovered the Pyramid Texts during excavations in 1880 at a site in South Saqqara. He found hieroglyphic text covering the walls of subterranean rooms within the pyramid of Pepi I.
The Pyramid Texts first appeared in the pyramid of Unas, who was the last pharaoh of the Fifth Dynasty. A total of 283 spells appear on the subterranean walls of Unas' pyramid situated between the pyramids of Djoser and Sekhemkhet in North Saqqara.
Utterances 273 and 274 are known as the Cannibal Hymn because they describe the king hunting and eating parts of the gods to incorporate divine powers for passage into the Afterlife. This hymn appears first in the Pyramid of Unas and is also found only in the Pyramid of Teti.
Three queens from the Sixth Dynasty named Wedjebten, Neith, and Iput II had tombs containing Pyramid Texts alongside kings. Queen Neith was the wife of Pepi II and her texts were kept in much better condition than those of the kings.
Pyramid Texts were not written in the pyramids of pharaohs during the Middle Kingdom which spanned from 2055 BCE to 1650 BCE. However, traditions of the pyramid spells continued to be practiced even after this period ended.