The name Isis literally means “Queen of the Throne.” She was the mother figure in Egyptian mythology, and was both the sister and wife to Osiris. She was a funerary deity, like Osiris, and thusly became his wife by association. She and her sister, Nephthys often appeared on coffins, with their wings spread, to protect the soul within from evil, as it traveled to the afterlife.
In Egyptian mythology, Nephthys became sexually frustrated with Set, and disguised herself as Isis to try to seduce him, but the plot failed, and instead, she gained the attention of Osiris, whom, thinking her to be Isis, coupled with her, and she gave birth to Anubis. Fearing Set’s anger, Nephthys persuaded Isis to adopt Anubis, so that Set wouldn’t find out.
Set was however, the enemy of Osiris. In one story, Set held a feast for Osiris, and brought in a beautiful box, saying that whomever could fit in it, could keep it. Set had already measured Osiris while he was sleeping, and knew he was the only one who would fit perfectly. Once Osiris was in the box, Set closed the lid, so that it was now Osiris’ coffin. Set threw the box far out in the Nile, and Isis went looking for it so she could bury Osiris properly. She found the box, and hid it, but Set went hunting that night, and found it. So that Isis could never get Osiris back whole again, Set chopped his body up into fourteen pieces and scattered them all over Egypt. Isis and Nephthys went searching and found thirteen of the pieces, but the last piece, his penis, had been swallowed by a fish, so Isis made one out of gold. Isis managed to bring him back for one night with her magic, in which they conceived Horus.