Set had been jealous of his brother Osiris´ power and popularity for some time .When Osiris decided to travel the world to bring civilisation to its people, he made Isis (his wife and sister) Regent of Egypt instead of Set. Set vowed to kill his brother and take the power he considered to be rightfully his. Set invited Osiris to a banquet and had a beautiful cedarwood and ebony chest made for the occasion. He offered the chest to anyone who could fit into it. Just as Set planned, none of the other guests fitted the chest perfectly, the only person left to try was Osiris. When he lay down in the chest, Set slammed on the lid and nailed it down. He sealed it with molten lead and threw it in the Nile.
The chest floated down the Nile ,was swept out to sea and landed on the coast near Byblos. The instant it touched the land, a huge Tamarisk tree sprouted up and absorbed it into its trunk. The king of Byblos admired the tree and cut it down and set it up as a pillar in his palace with the coffin still hidden inside. Isis tracked his body to Byblos and persuaded the king to give it to her . She took her husband´s corpse back to Egypt and used magic to concieve his child, Horus . However, Set found Osiris´s body unattended. He cut the corpse into fourteen parts and distributed them around Egypt. Isis was distraught, and enlisted the help of her sister and Set´s wife, Nephthys. They found all but one of the pieces, his penis, which was eaten by a fish . Isis and Nephthys mourned over the dead body of their brother and Ra took pity on them. He instructed Isis to piece the body back together, with the help of god Anubis,and swathed it in linen and clay.She fanned the cold clay with her wings and Osiris revived to reign as king of the dead in the otherworld.
Osiris was also a god of grain often depicted with grain growing from his body while lying face up.. Every harvest, the grain god was symbolically killed and his body broken on the threshing room floor, but after the inundation of the Nile river life would return to the land and the grain would grow again.