Inside the pyramids we find the Pyramid Texts, from which we get much information about Re. The Pyramid Texts describe the journey of the dead pharaoh through the underworld.
The story of Re says that Re rose in the beginning of creation. He then spat forth Shu and Tefnut, who became the first godly couple. They gave birth to Geb and Nut - the Earth and sky. Geb and Nut then gave birth to Osiris and Isis, and Seth and Nephthys. Osiris is murdered by his brother Seth and then made the god that rules over the dead.
