According to D.J. Conway's book Moon Magick, July 19 is the date of the Egyptian New Year. The Opet Festival or Marriage of Isis and Osiris. There is a fair amount of disagreement about the Egyptian calendar and how it relates to the calendars we use today. Some sources base the dates on the rising of Sirius, the dog star, which varies from year to year, while some list this date as August 1.
From the book Sacred Mysteries, here is a simplified story of the legend of Isis and Osiris:
The ancient Egyptian myth of the marriage of Isis and her brother Osiris begins before the creation of the world, in the womb of the mother goddess of the night, with the twins twisting and twining together in the throes of first love.
When they are born, the world is born with them, and the opposites of day and night, male and female, life and death emerge from the primordial abyss of the deep. Osiris has a wicked brother, Set, and Isis a sister, Nephthys, who emerge together as a divine family from the chaos of the cosmos.
As with all marriages, family complications form the context for the relationship of Isis and Osiris.
One day, Set, the wicked brother, envious of the power of Osiris, pulls a memorable prank during a wild party. He brings a coffin cut to the precise measurements of Osiris into the room, and asks who would like to try it out. At the stroke of midnight, at the peak of the party, Osiris climbs into the coffin, much to the amusement of the guests. But at that moment, 72 cohorts of Set rush out of the dark corners of the palace and nail the coffin shut, trapping Osiris inside. Then they throw it into the river, and the bier floats up the Nile like a barge, to a place called Abydos.
A princess who has just given birth takes the sweet smelling cedar wood out of the river, and erects it in the courtyard of her riverside palace, where an incense-bearing tree springs up to enclose the coffin.
Meanwhile, Isis, the bereft sister-bride, tracks her brother's coffin down, and comes to the palace of Abydos. Disguising herself as a mortal nursemaid, she gets a job watching after the child born to the princess.
Each night, Isis resumes her divinity, and, after anointing the boy with ambrosia, dips him in the fire on the hearth to purge him of his mortality. As the boy sits happily squealing in the flames, Isis turns herself into a sparrow, and flits lamenting around the erica tree in the courtyard, in which Osiris lies entombed.
One night, awakened by the song of mournful sparrow, the princess bursts into the nursery-only to find her little boy cavorting in the flames. The princess lets out a shriek which breaks the spell. Isis assumes her divine form and chastises the bewildered mother:
"If only you'd let me be, your boy would have become immortal. But now, he must die, like all men and women."
The princess is overcome with grief, and awe, in the presence of the goddess.
"By the way," Isis continues, "you've got my husband's coffin in the erica tree growing in your courtyard. Would you mind giving it me please?"
The princess complies, and Isis floats off down the Nile on a barge bearing the bier of the dead Osiris. Flapping her wings over his mummy, Isis revives the dead god, and makes love to him.
This will not be the last time in the sacred mysteries of marriage that a husband or a wife is brought back to life by the power of love.
The child born from the union of Isis and Osiris represents the perennial emergence of life from death. His name is Horus, the hawk-headed deity, and he will play a crucial role in the second death and resurrection of his father Osiris.
After giving birth to Horus, Isis sits suckling the baby in the reeds alongside the river-the first Madonna, and the first savior of our religious and mythological tradition.
While she sits happily nursing the boy, the wicked brother Set finds the mummy of Osiris, and tears it to shreds, scattering the pieces of the body all over Egypt. With the help of his son Horus-who is able to get a little distance from the situation by flying high over the land-the various pieces of the dismembered corpse of the father are put back together.
What was lost is found.
Horus gets above it all, gaining that higher perspective we need in marriage to cope with its rhythms of death and rebirth.
All of the pieces are recovered, with the exception of the phallus-which a fish has swallowed! Isis has to make the first prosthetic penis, and rouse it to life by flapping her wings over her dead husband.
An eye Horus has lost in a battle with the wicked brother Set is also needed to bring the father back to life. It represents the insight we need to penetrate the mysteries of our relationships, and bring us out of the dark moments.
The resurrected Osiris becomes the Lord of the Underworld, to whom all of the dead are brought for judgement, and for rebirth in the spiritual kingdom to come. He sits on a magnificent throne, with 24 cobras sitting in a row above him. The snakes' hoods are erect, bearing solar disks on them.
Behind the throne stand Isis and her sister Nephthys, their arms uplifted in a gesture of reverential support.
Without his wife, Osiris would be a rotting corpse on the bottom of a muddy river.