Isis is the Great Mother, Moon Goddess, Giver of Life and the Goddess Supreme. In Isis's role as Tait, Isis weaves the threads of the Tat or Knot of Fate. Isis is mostly identified with Demeter, Hera and Selene, being that Isis is ruler of the moon, agriculture and protector of marriage.
There were festivals in the spring and autumn to honor Isis, but Isis's most prominent celebration was the Night of the Teardrop in June. It is a night to remember the losses of Isis and Isis's eternal mourning for Osiris. It has been said that the priestesses of Isis could control the weather simply by braiding and releasing their hair. Supposedly the art of making magickal knots and blowing on them was taught to the humans by Isis and that alongwith her husband Osiris ,Isis taught humans to spin flax, grind corn, weave cloth and cure disease. Isis was the patron of marriage, the moon, divination, motherhood, agriculture, protection, reincarnation, initiation, fertility, magick, purification and domestic life. The cow, the buckle of Isis and the sistrum were sacred symbols to Isis. Isis is commonly portrayed with protective winged arms and the moon perched upon her head. Isis is a sacred part of the holy trinity along with Osiris (the father) and Horus (the divine son).
When Isis was young Isis decided to increase her magickal prowess by tricking Ra into giving her a measure of his power. Isis waited until Ra was at the end of his reign and weak. Isis then took dirt and a measure of his saliva to create an invisible snake that bit and poisoned the god. Ra was unable to cure himself because he did not know the cause of the wound. Isis offered to heal him but only in exchange for his secret name. Ra eventually gave in and told Isis his true name, thus passing his knowledge directly to Isis.
Meanwhile, Nephthys was unable to have a child by her husband Set and so lay with Osiris. The child of that union was Anubis, who was abandoned soon after because Nephthys feared Set would destroy the child. Isis found young Anubis and raised him herself. Isis eventually married Osiris.
When Seb and Nut abdicated the throne, they passed rulership of Egypt to Osiris and Isis. Set however was jealous and wanted the throne for himself. When Osiris returned from a journey to Memphis, during which Isis ruled in his absence, Set and his followers invited him to a banquet. Set brought out a magnificent chest and stated that whoever could fit inside it would be given it as a gift. Osiris climbed inside and of course it was a perfect fit.
Set and his followers then nailed the lid shut, covered the box with melted lead and threw it into the Nile. It floated out to sea where it eventually washed ashore at Byblos and a tamarisk tree grew up around it. Because of this Nephthys left Set and the other gods abandoned him and took refuge in the bodies of animals. Set himself took the throne of Egypt.
When the tamarisk tree was cut down to make a pillar in the palace of the Phoenician king of Byblos, it gave off an exquisite scent. So wonderful was it that Isis recieved word of it in Egypt. Isis traveled to Byblos and retrieved the chest, hiding it in the swamps that belonged to Buto, the cobra goddess. Then, using the magick Isis learned from Thoth, created light with her hair, wind with her wings and revived her husbands body long enough to concieve a child with him. Isis remained a guest of Buto, hiding in the swamps unti Isis's son Horus was born.
Set had no intentions of giving up his throne and while hunting, found the chest that still held the body of Osiris. Unfortunately Isis was absent so Set cut Osiris's body into 14 pieces and scattered them throughout Egypt. When Isis returned she was grief-stricken and immediately went looking for the pieces of her husbands body. Isis found all the pieces but one, for Osiris's manhood had been eaten by a Nile crab.
With Nephthys help, Isis joined the pieces together. Then with additional help from Anubis, Thoth and Horus, Isis performed the first rites of embalming and the Rite of Rebirth, giving Osiris eternal life. Osiris then ascended to the immortal world and Isis hid her son from Set, again in the swamps of Buto, until Horus was strong enough to avenge his father.
To make him strong Horus was exposed to many dangers. He was attacked by wild beasts and poisoned by scorpions. Always the magick of Thoth and Isis saved him. As he got older, Osiris came to teach him how to use weapons, all so that Horus could eventually claim the throne which was his by birth and take his revenge upon Set.
The day then came when Horus challenged Set for the throne and petitioned the tribunal of the elder gods to pass judgement on who was the rightful heir to the throne of Egypt. The tribunal, of which Ra was the head, became deadlocked over the issue. To help settle the dispute, Thoth asked the goddess Neith, who was the World Mother, to advise the tribunal. Without hesitation, Neith declared that Horus was the rightful ruler. All the gods agreed with her judgement except for Ra, who believed Horus was too weak to take the throne. It appeared as if Horus would be declared ruler but the tribunal had yet to hear Set's testimony.
Set had only one advantage and that was his serpents tongue. He convinced the gods that it was his great strength that protected the sun barge on it's journeys through the underworld during the night. He implied that Horus had not the strength to do this duty. The entire tribunal then swung it's vote in favor of Set, with the exception of Thoth. Thoth attempted to speak up for Horus and Isis began laying curses upon everyone, terrifying the tribunal.
Set was furious and threatened to kill one god each day until the tribunal voted in favor of him. He also refused anymore discussion on the matter unless Isis was barred from the tribunal. To please Set, Ra removed the tribunal to an island, giving Anti the ferryman instructions that no woman was to cross.
Isis would not give up however, so Isis disguised herself as an old woman and bribed Anti into letting Isis cross. There Isis shapechanged into a beautiful young maiden and inticed Set away from the meeting. Isis then told Set that she was a widow who had a young son whose inheritance was stolen by a foreigner. Set, being besotted by the disguised Isis, replied that the son was the rightful heir. At that, Set realized the rightful judgement came from his own mouth and angry, returned to the tribunal to tell them what happened. The gods then had no choice but to rule in favor of Horus.
Set would not accept the ruling however and demanded a trial by combat with Horus. First they changed into hippos and dove into the Nile to see who could hold their breath the longest. Isis began to worry about her son and threw a magickal spear into the water, accidentally hitting Horus with it. Horus came out and demanded that Isis remove the spear, then he returned to the water. Isis again threw the spear and this time hit Set with it. Set appealed to Isis to remove the spear and she did. Horus, in a fit of anger over his mothers interference and her aid to Set, cut off her head. Ra was aware of the situation and asked Thoth to remedy the problem. Thoth replaced Isis's head with that of a cow. Another version says that Horus only tore off his mothers diadem and Thoth replaced it with one shaped like a cow.
During the battle, Thoth was called upon to heal Set's manhood with his saliva. Set retaliated by creeping up to a sleeping Horus and gouging out his eyes. Hathor stepped in and healed Horus. During this time, it was Thoth's responsibility to see that balance was kept. Eventually Ra tired of the affair and demanded that the tribunal settle the dispute in favor if Isis's son. Horus was declared the rightful ruler of both upper and lower Egypt. Horus declared Thoth his grand vizier and when he later resigned, accepted Thoth as his heir.
Everyone was satisfied with the verdict except Set. He would repeatedly cause trouble, prompting Isis to plead to the tribunal to do something about him. They did not exile him like Isis would have liked, but instead gave him the desert and all foreign lands as his domain.