history, so the Eye of Horus must have originally had some other significance. Because many concepts in Egyptian belief are fluid, the roles of the two eyes frequently overlapped. One such area of overlap is that in myth, both Horus and Ra lose their respective eyes. Katja Goebs argues that the myths surrounding the two eyes are based around the same mytheme, or core element of a myth, and that "rather than postulating a single, original myth of one cosmic body, which was then merged with others, it might be more fruitful to think in terms of a (flexible) myth based on the structural relationship of an Object that is missing, or located far from its owner". The Pyramid Texts from the Old Kingdom (c. 2686–2181 BC), one of the earliest sources for Egyptian myth, mention both the Eye of Horus and the Eye of Ra. Roles Solar The yellow or red disk-like sun emblem in Egyptian art represents the Eye of Ra. Because of the great importance of the sun in Egyptian religion, this emblem is one of the most common religious symbols in all of Egyptian art. Although Egyptologists usually call this emblem the "sun disk", its convex shape in Egyptian relief sculpture suggests that the Egyptians may have envisioned it as a sphere. The emblem often appears atop the heads of solar-associated deities, including Ra himself, to indicate their links with the sun. The disk could even be regarded as Ra's physical form. At other times, the sun god, in various forms, is depicted inside the disk shape, as if enclosed within it. The Egyptians often described the sun's movement across the sky as the movement of a barque carrying Ra and his entourage of other gods, and the sun disk can either be equated with this solar barque or depicted containing the barque inside it. The disk is often called Ra's "daughter" in Egyptian texts. As the sun, the Eye of Ra is a source of heat and light, and it is associated with fire and flames. It is also equated with the red light that appears before sunrise, and with the morning star that precedes and signals the sun's arrival. Procreative The eyes of Egyptian deities, although they are aspects of the power of the gods who own them, can behave as independent beings in mythology, possibly because the word for "eye" in Egyptian, jrt,