The first time we see the name of Osiris, written inside a pyramid, happens during the Fifth Dynasty of Egypt. One of his titles, "Foremost of Westerners," dates back a few hundred years earlier. Osiris gets a lot of titles, and shares them, too. All dead people are allowed to call themselves Osiris in his honor.
The world's first party plan: the priest Ikhernofret writes down all the things he had to do for the Osiris Mysteries, and leaves us a very detailed stela (a carved stone tablet) with the five-day festival schedule. It probably took him a while to fold 3,000 origami crocodile hats!
Osiris wants to go visit Greece, so he asks for a Greek name that everybody up there can pronounce. King Ptolemy decides to call him Serapis, or "Osiris the Bull," and asks him to wear some of Zeus's clothes to the temple so he'll fit in better.
This essay, from Plutarch's fifth book of the Moralia, is one of the only full versions of Egyptian myth about Osiris. Even though he was a Greek-speaking Roman, Plutarch loved the stories he heard about Isis and Osiris so much that he made sure they were written down for everyone.
The Orthodox Patriarch Theophilius of Alexandria leads a group to destroy Serapis' ancient temple in Alexandria, and bans Serapis' public worship.
A boy and a girl who can't be together… who do they pray to? Isis and Osiris, the first gods who were separated against their will. Mozart's fantasy opera includes prayers to Isis and Osiris.
Each summer in Egypt, when the sandstorms come out of the Sahara and it gets super hot and dry, the Nile starts to recede, and the green land dies and becomes brown and sandy. This is when Seth (the god of the desert) "kills" his brother Osiris. Around mid-September, when the weather shifts and the Nile rises again, Egyptians celebrate the "Night of the Drop," "Leilat al-Nuktah." The drop comes from Isis' tears falling in the river (how sad is that?).
The ancient Egyptians knew the constellation Orion as Sah, or "the Strider," and considered it a form of Osiris in the sky. It rises above Egypt around November, at the time when the ancients celebrated the Osiris Mysteries in the god's honor. Orion's belt has three stars in a diagonal, just like the rows made by the Three Great Pyramids at Giza.