Mysteries of Osiris
The Mysteries of Osiris, also known as Osirism, were religious festivities celebrated in ancient Egypt to commemorate the murder and regeneration of Osiris. The course of the ceremonies is attested by various written sources, but the most important document is the Ritual of the Mysteries of Osiris in the Month of Khoiak, a compilation of Middle Kingdom texts engraved during the Ptolemaic period in an upper chapel of the Temple of Dendera.