The Neolithic concept of a "solar barge" (also "solar bark", "solar barque", "solar boat" and "sun boat", a mythological representation of the sun riding in a boat) is found in the later myths of ancient Egypt, with Ra and Horus. Predynasty Egyptian beliefs attribute Atum as the sun-god and Horus as a god of the sky and sun. As the Old Kingdom theocracy gained power, early beliefs were incorporated with the expanding popularity of Ra and the Osiris-Horus mythology. Atum became Ra-Atum, the rays of the setting sun. Osiris became the divine heir to Atum's power on Earth and passes his divine authority to his son Horus. Early Egyptian myths imply the sun is within the lioness, Sekhmet, at night and is reflected in her eyes; or that it is within the cow, Hathor, during the night, being reborn each morning as her son (bull).